Whether you have had a freshwater aquarium before or are entirely new to the aquarium hobby, this article will help you sort through all the options to determine what is needed for a saltwater fish tank?

Creating and maintaining a thriving, beautiful saltwater fish tank takes time, patience, money, and the right gear, gadgets, and supplies. Here is a quick summary of what is needed for a saltwater fish tank:

Equipment needed for a saltwater fish tank

1. The aquarium itself
2. A stand: capable of supporting the weight of the tank
3. A lid: to help prevent fish from jumping
4. Lights: set on a timer for 8-10 hours each day
5. Heater and/or Chiller: for temperature control to warm up or cool down water as needed
6. Water circulation pump: for water movement and oxygenation
7. Filter: if the tank is not filled with live rock
8. Gravel vacuum: for water changes and maintenance
9. Hydrometer or Refractometer: for testing salinity/specific gravity
10. Buckets: for water changes and acclimating new fish and invertebrates
11. Plastic containers: for catching, transporting, or acclimating fish and inverts
12. Thermometer: for measuring temperature

Substrate and decorations needed for a saltwater fish tank

1. Live rock: Porous reef rock to create some reef aquascape, provide hiding spots and places to mount corals
2. Live sand: Helps jump-start the biological diversity in the tank and makes the bottom of the tank look nice
3. Decorations: To personalize your tank and give it the look you want

Supplies needed for a saltwater fish tank

1. Reef salt mix: for making salt water, you’ll need a lot of this, and it’s heavy
2. Test kits: for testing critical water parameters
3. Coral dip: for treating corals before adding them to the fish tank
4. Kalkwasser or a Two-Part supplement: for Calcium management
5. Replacement filter media: if using a filter

Food needed for a saltwater fish tank

You don’t need to buy all of these all at once, but over time, it is generally good to provide a variety of options.

1. Live foods: Blackworms, Brine shrimp, Mysis shrimp, Feeder shrimp, depending on what animals you are feeding
2. Frozen foods: In your pet store freezer–brine shrimp, mysis shrimp, veggie blends
3. Pellets or Flakes: These nutrient-packed prepared foods help make feeding time convenient

There are a lot more items that will be covered in this article that you could add, but the list above is what is needed for a saltwater fish tank.

Additional equipment that can be helpful for a saltwater fish tank

In addition to what is needed for a saltwater fish tank, there are a lot of optional items that are not 100% necessary but can improve your experience. Here are a bunch of the most popular and useful items to consider supplementing with what is needed for a saltwater fish tank.

1. Protein skimmer: specialized equipment that cleans saltwater; not 100% necessary but helps significantly.
2. Sump: a reservoir below the tank, usually in the stand, that houses additional water and keeps the equipment out of view
3. Refugium: a dedicated area where natural algae and invertebrates grow and purify the water
4. Target feeder for corals: specialized gear to help feed corals
5. Magnet glass cleaner: makes keeping the aquarium glass clear of algae easy
6. Nets: for chasing or catching fish
7. Quarantine tank: for observing fish before adding to your tank and treating parasites
8. RO/DI: A water purification system to turn your tap water into the best possible reef water
9. Reactors: equipment that holds media that reacts with chemicals in the water, removing them
10. Dosers: small pumps that add nutrients/supplements consistently
11. Automatic Top Off: Automatic pump system that replaces evaporation
12. Reef Journal: A place to plan out your fish tank, record your progress and test results
13. New Saltwater Aquarium Guide: A guide to setting up your new tank

Water quality: testing what is needed for a saltwater fish tank

Maintaining high water quality is everything in a saltwater tank. In some respects, success is as much about caring for the water as it is about caring for the fish in the fish tank.

Here are the most important water quality measurements to do what is needed for a saltwater fish tank:

• Salinity: how much salt is in the water, typically measured as specific gravity with a hydrometer
• pH: saltwater needs to have a higher pH than freshwater
• Temperature: saltwater fish come from warm, tropical reef waters
• Ammonia: a poisonous pollutant that needs to be filtered out
• Nitrites: an intermediate compound created when your filter processes ammonia
• Nitrates: the chemical compound created when ammonia is converted in your filter. This waste product is less toxic than ammonia but needs to be managed in a saltwater fish tank.
• Alkalinity: used to estimate healthy levels of an essential compound to corals called bicarbonate
• Calcium: a critical element for healthy corals
• Phosphates: a trace nutrient that becomes problematic in large quantities

To test for and measure these water parameters, you will need equipment, including a hydrometer and thermometer, for measuring salinity and temperature.

You will also need test kits or strips for measuring ammonia, nitrites, nitrates, alkalinity, calcium, and phosphates.

Check out this full-length article on the most important water parameters for more information.

Dealing with potential problems

We all face problems while trying to keep our saltwater fish tanks pristine and clean. The three most likely problems you will encounter are:

1. Nuisance algae: problematic for almost every new tank and periodically even once the tank is established. The biggest algae problems are dinoflagellates, diatoms, cyanobacteria, hair algae, bryopsis, and bubble algae.
2. Parasites: saltwater ich, marine velvet, and other parasites weaken fish and spread in our tanks if we don’t correctly quarantine
3. Unwanted hitchhikers: aiptasia anemones, bristle worms, red bugs, and other creatures travel into our tanks on rocks and corals and can plague our inhabitants.

Related article: 23 Quick Tips for Dealing with Aquarium Algae

Related article: Treating saltwater ich

Related article: Hitchhiker’s guide to live rock

What is needed for a saltwater fish tank: the best first fish

The best first fish for a new saltwater tank will be relatively inexpensive, hardy, and proven by many people to be successful in an aquarium. Specific care guides and lists of the best first fish are their own topics, but to get you started, here are three of the best first fish:

1. Clownfish: 94% of aquarium enthusiasts reported success caring for clownfish
2. Wrasses: 89% reported success caring for wrasses
3. Cardinalfish: 88% reported success caring for wrasses

Related article: Powerful coral care and saltwater fish statistics

Related article: 5 Best saltwater fish for beginners

How many fish for a saltwater fish tank, and what are the best combinations?

The number of fish for a saltwater fish tank will vary based on the size of the tank, the size of the fish, the combination of fish, and the amount of space each one needs. To review custom recommendations, check out these popular stocking guides by tank size:

When to add the first saltwater fish

The first appropriate time to add your first saltwater fish is after the tank has completely cycled. Let’s explore what that means. A fish tank, by definition, is a reservoir of water you keep in your house and ideally doesn’t leak. That means nothing goes in or leaves the tank without you handling the details.

The saltwater fish and invertebrates you add will go about their business and do their own biological functions if you catch my meaning.

You will also add food that won’t get entirely eaten. All of that stuff eventually creates waste. One of the key waste products that will build up (at first) is ammonia. Unfortunately, ammonia is a toxic chemical.

Fortunately, naturally occurring bacteria will colonize your tank, all on their own, or with the help of additives or special products you can buy, like live rock and live sand. Those first, naturally occurring and beneficial bacterial will consume the ammonia and turn it into nitrites (spelling is important there, as you’ll see in a moment).

Those nitrites are problematic in freshwater but not-so-problematic in saltwater. However, either way, we are fortunate that there is another group of bacteria that like to consume the nitrites and leave nitrates behind as a waste product.

Once your tank has built up the natural colonies of bacteria that you need to do all that waste management, your tank is said to have cycled.

That means the tank has been up and running, and you don’t detect any ammonia or nitrites with test kits or test strips, even with waste products (decaying food or ammonia additives) inside the aquarium water, because the bacteria are efficiently converting it via that multi-step process into nitrates.

If you add your first fish before that is done, you will burn them. Chemical burns. Nobody wants to see you create the next Joker (Batman reference) in your tank.

So please check to see that your saltwater fish tank has cycled before adding your first saltwater fish to the tank.

Related: How to cycle a saltwater fish tank

What is needed for a saltwater fish tank: the best beginner corals

If you plan to add corals to your saltwater fish tank, an important first step is to pick those coral types that you are likely to have success with. Success breeds more success in this hobby. Here are a few of the best beginner corals to add to a new saltwater fish tank:

1. Mushroom corals: 92% of people reported success with mushroom corals
2. Green star polyps: success was reported 85% of the time with GSP
3. Toadstool corals: 82% of people were successful with toadstool corals

Related article: 27 Best beginner corals

When to add your first corals

Determining when to add your first corals is a bit of a tricky topic. Some of the best beginner corals will act like pioneers, helping you colonize the new frontier you have created and help carve out a space and compete with the inevitable algae problem.

However, those first corals are also likely to succumb to the fluctuating water parameters and the problems that those nuisance algae will cause.

You certainly could start sooner if you were very eager to get your hands wet with corals, but I think a reasonable starting point estimate would be to wait until your tank has progressed through the various algae stages.

While not every tank will experience all the stages, the first ‘algae’ to pop up are brown dinoflagellates, diatoms, cyanobacteria, hair and bubble algae, and then finally coralline algae and stability.

Once those problem algae are out of the way and the coralline algae take over (should be between 6 months and a year), your tank is in the best shape it is going to be to give you the greatest chance of success with corals.

In all fairness, that might also be doing it the hard way, so if you want to get started a little early, start with that list above of the hardiest beginner corals because they are fast enough to potentially out-compete those problem algae.

Best cleanup crew: what is needed for a saltwater fish tank

One of the coolest things needed for a saltwater fish tank is also one of the most fun–it is called a clean-up crew. What is a clean-up crew? It is a combination of invertebrates that will help stir up the sand, eat unwanted or leftover food, munch on algae and help remove the unwanted things.

Here are a few of the best cleanup crew members:

1. Hermit crabs: able to climb to the hardest-to-reach places, they are great scavengers
2. Cerith snails: MVP of the clean-up crew. They are small but tackle the tough problems
3. Emerald crabs: Make short work of hair algae problems

Related: 23 Interesting invertebrates that also eat algae

Maintenance tasks: what is needed for a saltwater fish tank?

Each day

• Feed your fish 2-3 times
• Wipe down aquarium glass to clean off algal film
• Dump the protein skimmer cup to remove the skimmate

Each week

• Perform a 10-20% water change (at least until you get the hang of it). You want to suck up as much muck, gunk, algae, and detritus as you can, during your change. Extra credit for having a gross bucket of water
• Test your water 2-3 times each with all the kits or strips you own, targeting the major water parameters, and record it in your Reef Journal.
• With a wet rag (fresh water, no chemicals,) wipe away any accumulated salt deposits on the lid (called salt creep, it will keep growing if you don’t get rid of it).
• Replace any water you lost to evaporation with aged, chlorine-free fresh water (RO/DI is best, but aged tap water is fine). Keep track of how much skimmate you’ve removed because you want to keep salinity neutral, and the skimmate removed will be saltwater, not freshwater
• Clean out the protein skimmer cup and neck to aid in efficient skimming
• Feed your corals 1-2 times

Cost and how much money: what is needed for a saltwater fish tank

You can truly spend however much money you want on a saltwater tank, and you will probably spend more money than you think. In a 2022 survey of Saltwater Aquarium Enthusiasts, 18% spent $500 or less on their setups, but the median cost was between $1,000- $1,500.

As you can see from the chart above, however, the initial setup cost was spread throughout the range. In addition, there was a sizeable number of people at every cost threshold, suggesting that the upfront investment cost is somewhat up to the aquarium owner to decide.

Best advice and tips: what is needed for saltwater fish tank success

1. Install a grounding probe: to avoid shocking yourself
2. Nets: better used to chase fish into a clear container than the other way around
3. Save money: by mixing less expensive dry rock with live rock–it all becomes live rock, eventually

Related: Best saltwater aquarium tips for beginners

Quarantine

When I had freshwater tanks, I never quarantined them. I also never worried about it. Sure, diseases and parasites showed up, but I just ran out to the store, bought some meds, turned my tank blue or green for a few days, and the problem was over.

I’m sure I also suffered my share of losses, but freshwater fish are cheap. I don’t mean to be callous. Just saying I never gave it much attention.

When I converted to the saltwater aquarium hobby all those years ago, I brought those bad habits with me, arrogantly reinforced by my self-perceptions of freshwater success.

I’m here to report that things ended badly for me twice. I’m talking total tank crashes due to crazy parasite problems. You can’t treat parasite problems effectively in a reef tank because anything you would use (that works!) will kill your invertebrates and corals.

The only way to treat parasites is in isolation. It is tough to get fish out of a reef tank, and it is challenging to eradicate parasites once they get in your reef tank. The solution to these problems is quarantine. Please read up on it.

Related: How to quarantine for a saltwater tank

What is needed for a saltwater fish tank that is different from freshwater?

There are a lot of similarities between keeping a freshwater tank and a saltwater fish tank, but there are also a few unique elements needed for a saltwater fish tank.

Similarities with freshwater

The fundamentals of managing a saltwater fish tank are essentially the same as with freshwater–you need to understand the care needs of the fish you want to keep, and you need to meet them while also maintaining stable, pristine water conditions in the tank.

• A biological filter converts waste ammonia into nitrates.
• Water pumps help oxygenate and circulate the water
• Heaters warm up the water to tropical temperatures
• Water changes and maintenance keep things stable.

A saltwater fish tank with corals is more like managing a planted freshwater tank and/or delicate fish like discus.

What is needed for a saltwater fish tank that is different from freshwater

Corals are not plants and not exactly traditional ‘animals’, per se, but they have care needs similar to both. That means they need high-quality lighting, like plants, but also need to be fed, like animals, and adequate water flow is essential to helping them get enough oxygen and remove their waste.

Many fish and invertebrates are more sensitive to fluctuations in water quality than the freshwater hobby.

Building and maintaining a saltwater tank is much more expensive.

Parasites, diseases and pests can be catastrophic and cause much more damage in saltwater (which is also much more expensive).

Biological filtration is vital in both fresh and saltwater, but in saltwater fish tanks, special rocks called live rocks, are placed inside the tank and serve as the reservoir for the bacteria that help clean the water. That is very different from a freshwater tank, where those bacteria are generally housed on a biowheel or in the sponge inside the filter.

This may have seemed obvious; salt water is needed for a saltwater fish tank. But, that isn’t made with table salt, or even the small box of ‘aquarium salt’ on the shelf at your big box store. Saltwater is made from a blend of salts and nutrients to recreate the specific levels of major and trace elements as ocean reefs.

Related: How to make saltwater for a saltwater fish tank

Related: Converting from freshwater to saltwater

Is it better to have a small tank or a larger tank?

Many people in the echo chamber reiterate some old standby advice that bigger is better in the saltwater aquarium hobby, but that is not always the case.

Bigger almost always means more expense, and it also almost always means more work- unless you have additional equipment to help make the work more manageable. At that point, you need to see my first point, which means that it means more expense.

Bigger tanks also weigh a lot more, which can often limit your options of where you can keep the tank or even require you to structurally reinforce your floor.

Here’s what my crawl space looks like:

What was that point I was making? Oh, right, bigger is NOT always better.

Smaller can be less expensive and easier to manage. Chores will take a fraction of the time, and you’ll run out of space sooner, which means it will cost you less. In addition, you will need less and smaller equipment, so running costs will also be lower.

With that said, people say bigger is better because water is generally pretty good at staying stable, unless we make it up, and a lot of water is better at staying stable than a little bit of water. So, since stability is a big part of the game here, size has THAT advantage.

But contrary to the norms here, it makes a lot of sense to start out relatively small. You can get a sense of how easy or hard it is to manage a saltwater fish tank without spending a fortune.

You also eliminate the risk that your new hobby feels more like a part-time job that you have to pay for.

You could start with any size tank you want, but for me, the sweet spot is between 20 gallons and 75 gallons.

Styles of saltwater fish tanks

What is needed for a saltwater fish tank will vary a bit based on what style of aquarium setup you want to have. However, here are a few ideas to get you started.

Fish Only

A fish-only saltwater tank is the easiest type of aquarium to set up and is the most like a freshwater fish-only aquarium. You need good filtration, enough aquascape, and decorations to make your tank look great and make your fish feel safe, but it is as simple as you can get.

Having a fish-only tank does allow you to keep certain species that might otherwise be problematic in combination with certain species.

For example, you could create a community of aggressive saltwater fish species that would not be appropriate for a community tank. However, many large, aggressive fish are also some of the easiest to care for (as long as you keep them separate from their prey).

You could also potentially keep some of the more delicate non-reef-safe fish, like large angelfish or butterflyfish. But keep in mind that would be a high complexity/difficulty tank.

Fish Only With Live Rock (FOWLR)

A FOWLR tank is a Fish Only With Live Rock tank. The name says (most of) it all. You have fish and live rock to create a natural substrate and performing the biological filtration for the tank, but you don’t have corals.

This is often the gateway tank that people start with. Once success has been reached with saltwater fish, people often want to create a mixed reef–and if you start out with a live rock aquascape, the ‘bones’ of the tank will already be there for you to put your corals on when, and if the time presents.

There aren’t any advantages between FOWLR vs. FO other than ease of upgrade and a more natural look/feel.

Community Reef Tank

Many of us dream of that community reef tank–re-creating the coral reefs we see when we snorkel, scuba dive, or watch TV programs. Seeing fish and corals living harmoniously, beautiful colors flashing and swaying in the current.

This type of fish tank requires careful planning, special equipment (detailed above), and patience, but it is a very achievable goal.

Conclusions

Hopefully, you have enjoyed reading this article about what is needed for a saltwater aquarium. There are plenty of links in each section to dive deeper and learn about specific topics. If you have questions not answered here or there, please drop a comment below or join the newsletter to send me an email.

I look forward to connecting with you.

There are a lot of different types of wrasse available for the saltwater aquarium. This article will cover the 75 Best types of wrasse, including their scientific name, the maximum size they grow to as adults, in both inches and centimeters, the minimum tank size required to adequately care for them in gallons and liters, their care difficulty, relative aggressiveness, diet, and whether or not they can be kept safely with corals.

75 Best types of wrasse: care guide summary table

The table below lists the 75 best types of wrasse, with a care guide summary. If the table is wider than the screen you are viewing it on, you can scroll left and right on the table itself.

Table 1: 75 Best Types of Wrasse

Are wrasses hard to keep?

Most wrasses are not hard to keep. They are generally hardy and relatively easy to care for.

Easy to care for types of wrasse for a saltwater tank

Here is a table of relatively easy to care for wrasse types that are not hard to keep:

Table 2: Easy to care for types of wrasse:

Which wrasses are reef safe?

Table 3: Reef safe wrasses for a saltwater tank

17 Types of wrasse that are not reef safe or are somewhat reef-safe with caution advised

Table 4: 17 Types of wrasse that may not be reef safe

How many gallons does a wrasse need?

Different types of wrasse will require different amounts of water. The minimum number of gallons to keep the smallest types of wrasse is 15 gallons, and the largest wrasse types require 180 gallons of aquarium water or more.

Types of wrasse for a nano aquarium (minimum 15 gallons)

Table 5: 2 Types of wrasse perfect for a nano aquarium

Types of wrasse for a 55-gallon aquarium or larger

Table 6: 24 Best types of wrasse for a 55-gallon aquarium or larger

Do flasher wrasses need sand?

The following genera (plural for genus) need a sand bed to sleep in hide: and Anampses, Halichoeres, Macropharyngodon, and Pseudojuloides. That includes the Yellowtail, Yellow, Green, and Melanurus wrasses.

Wrasse tank mates: best and worst

Compatibility between saltwater fish types is challenging to review, because individual experiences sometimes conflict. The general disposition and typical aggressiveness level of a species is a primary, driving force, but the behaviors of individuals within a species will sometimes be more or less aggressive than the norm.

The relative size of the fish in any aquarium, as well as the order in which they are added to the tank will also play a role in competition for food or territorial aggression.

That is why we need to take the general advice and reports we read online (including this one) with a grain of salt, and whenever possible, use data to inform our decisions.

Best wrasse tank mates

In 2022, Saltwater Aquarium Blog Newsletter Subscribers who had experience with keeping one of the most popular wrasse species, the Six Line Wrasse, were asked to indicate which fish types they were successful in keeping with the wrasse and which species they had personal experience with being incompatible with their wrasse.

I used the tally of compatible and incompatible votes to calculate the percentage of the time the wrasse tank mate was compatible with the wrasse.

Table 7: The best wrasse tank mates, including a compatibility score

Worst wrasse tank mates

In general, Saltwater Aquarium Blog Newsletter subscribers had more successes than failures keeping Pseudocheilinus hexataenia with other wrasse tank mates. But here are the worst wrasse tank mates that demonstrated the lowest compatibility percentages:

Table 8: The wrasse tank mates with the worst compatibility scores

The most common incompatibility was mixing one type of wrasse with another type of wrasse. Two individual wrasses were successfully kept together only 62% of the time.

While it was not directly specified in the survey (the options were simply to indicate compatibility/incompatibility), dartfish and jawfish are notoriously docile fish. One would expect that the docile fish were likely pestered and harassed by a more aggressive type of wrasse.

Eels and lionfish are predators. I’d exercise caution beyond what it stated here and avoid mixing species, especially given the small sample size of the data here.

Can you have two wrasses in the same tank?

You can have two wrasses in the same tank, but it takes some planning and careful purchasing. Having two wrasses in the same tank was the number one reason for incompatibility between two fish types. Aquarium owners were successful keeping two wrasses together only 62% of the time, in a recent Saltwater Aquarium Blog Survey.

Here are a few guidelines that will help. If you want to keep more than one wrasse in the same tank, don’t plan to keep any of the wrasse types in the Pseudocheilinus or Macropharyngodon genus, as they are notorious for being incompatible with other wrasses. Unfortunately, that rules out the very popular Six-line wrasse, Mystery wrasse, and Leopard wrasse.

Aggression tends to be the worst between males, with more aggression between males of the same species and between males from different types of wrasse. Please keep in mind that, in captivity, it seems that the vast majority (read that as “all”, softened just a bit) of female wrasses turn male eventually, which will likely cause issues later on, so it is generally best to just keep 1 of a given wrasse type.

Which wrasses mix well together?

Here is a presentation from MACNA 2017 that goes deep on these wrasses, including which species can be safely combined in the same saltwater tank:

What to read next

Check out these other great guides:

27 Types of tangs

25 Types of saltwater angelfish

19 Types of clownfish

5 Pufferfish types

References

The Wrasse Guy

Michael, Scott W. Marine Fishes: 500+ Essential-to-Know Aquarium Species. TFH Publications, Inc. 2001.

A lot of popular LED light models have white and blue lights. Blue light is an important wavelength for photosynthesis (the process where plants turn light into sugar/energy).

Blue light is also frequently used to simulate dawn and dusk light cycles. For example, in an 8-hour photoperiod, an aquarist may choose to run a light with White and Blue LEDs as follows:

1. 12 PM to 2 PM: Blue LEDs only
2. 2 PM to 6 PM: Blue + White LEDs together
3. 6 PM to 8 PM: Blue LEDs only
4. 8 PM until 12:00 PM next day: all LEDs OFF

But the existence of the Blue LEDs, often set up on a different switch setting, as well as the tendency to use those lights in the evening, creates a question I hear fairly commonly.

Can I leave the blue light on in a fish tank?

Blue light in a fish tank should not be left on for more than 12 hours each day. No light in a fish tank should be left on more than 12 hours each day. The fish, invertebrates, and even photosynthetic plants or corals in your tank will be healthiest and grow best with 12-16 hours of darkness each day. If you occassionally forget to turn the blue light off in a fish tank, that is okay, just turn it off next time, or set it on a timer or smart plug, so that you don’t have to remember.

Is blue light bad for my fish?

It seems highly unlikely that normal blue light with typical aquarium use is bad for your fish. There are a few scholarly publications on this and related topics, but the findings across studies seem a bit confounding, at best.

For example, a couple of studies concluded that blue light damages fish eye retinas. This was studied in goldfish and zebrafish (called zebra danios in pet stores near me). They did demonstrate and publish results that showed blue light exposure increased signs of stress and damage to the cells in the retina.

But there are other studies that show blue light actually reduced the stress response in Tilapia, which is a food fish, but is also a Cichlid.

Another study showed that the development of baby guppies was stronger/faster/better in blue light than it was in green or red light.

A different study showed that the species of fish they studied preferentially swam to the areas illuminated with blue or green light, but swam away from yellow and red light.

Why would fish have an instict to swim towards a light that is bad for them.

Here is a table summarizing the studies involving blue light and its effect on fish

Blue light has also been demonstrated to be extremly important to the growth of corals. Most of the facilities that grow corals commercially use a light spectrum combination that is heavily skewed towards the blue light part of the spectrum called AB+ that has been shown to produce the best growth in corals. The top of the line reef aquarium lighting manufacturers, like the Radion XR 15 BLUE lights above my tank, provide templates to automatically use this spectrum and are specifically designed with EXTRA blue LED diodes.

Finally, if you have spent any time snorkeling, or in a deep pool, you noticed that the lower you go, the bluer the light gets. Now, I know not every fish comes from a blue ocean environment, they may spend their time on the surface, where the light would be more white. Also, many freshwater species are in yellow/brown/turbid waters. So perhaps they would be more impacted, but I’m not sure that study has been performed.

One final note–zebrafish are used in studies often as a developmental biology model. My hunch, suspicion, hypothesis is that the studies showing blue light damage to fish eyes were intended more to inform understanding the impact of the blue light from electronics on our eyes than they were intended to show that you shouldn’t leave a blue light on over your fish.

Will plants grow better if I leave the lights on?

Plants and other photosynthetic organisms grow best when they have both light and dark periods. During the light period, plants and photosynthetic organisms like zooxanthellae harness the energy in light to make sugar with carbon dioxide and water. During the dark period, these photosynthetic organisms are like any other organism, where they need to consume those sugars for energy. Blasting too much light, out of balance, disrupts the dark phase and results in less vigor, not more.

That is why it is important to establish a consistent and balanced photoperiod for your tanks, or when trying to grow photosynthetic organisms like phytoplankton. A photoperiod of 8 to 12 hours on and 12 to 16 hours off is typically ideal.

Can I leave blue light on in a fish tank to simulate moonlight?

Fish, coral, and other invertebrate spawnings are often tied to lunar cycles. So the notion of recreating moonlight in your fish tank, instead of just total darkness may encourage more natural cyclical behaviors. But blue lights should not be left on in a fish tank for longer than a few hours, to simulate moonlight.

I am currently running the Corallab AB+ template on Radion XR 15 Blue LED lights, and the program is set for a gentle 3 hour moonlight period, which also creates another interesting viewing opportunity. I enjoy watching the fish and corals start to get ready for the night as the moonlight program gets closer to ending.

You could also DIY your own moonlight by having a dim blue light, white light, or combination light mounted above the fish tank. If your LEDs are dimmable, you could set them up to brighten and dim in conjunction with a 28 day cycle to recreate the phases of the moon.

Roxanne, you don’ t have to put on the red light

I just like that song. Didn’t understand it until I got older :). I just counted, and that song repeats “put on the red light” 25 times. Yowza!

Related articles

Check out these other related articles:

Growing Phytoplankton at home

Best Reef Aquarium Lights

References

Noureldin, Salwa M., et al. “Effect of different monochromatic LED light colors on growth performance, behavior, immune-physiological responses of gold fish, Carassius auratus.” Aquaculture 538 (2021): 736532.

Ruchin, A. B. “Influence of colored light on growth rate of juveniles of fish.” Fish physiology and Biochemistry 30.2 (2004): 175-178.

Song, Jin Ah, and Cheol Young Choi. “Effects of blue light spectra on retinal stress and damage in goldfish (Carassius auratus).” Fish physiology and biochemistry 45.1 (2019): 391-400.

Volpato, Gilson Luiz, and R. E. Barreto. “Environmental blue light prevents stress in the fish Nile tilapia.” Brazilian Journal of Medical and Biological Research 34 (2001): 1041-1045.

Xu, Jiawei, et al. “A Detailed Analysis of the Effect of Different Environmental Factors on Fish Phototactic Behavior: Directional Fish Guiding and Expelling Technique.” Animals12.3 (2022): 240

Damselfish are some of the most popular saltwater fish, because they are inexpensive, easy to care for, and hardy. But they can also be aggressive towards other fish in a community tank.

Here are 21 Popular Damselfish Types listed alphabetically by common name:

Ideal water parameters for Damselfish in a saltwater tank

Most Damselfish types are hardy, easy to care for saltwater fish that do not have very demanding, specific care requirements. The traditional reef aquarium water parameters will be a great fit for them:

• Temperature: 73 to 84 Fahrenheit
• pH: 8.1 to 8.4
• Salinity: 35 ppt (1.025 specific gravity
• Ammonia: 0 ppm
• Nitrite: 0 ppm

1. Azure Damselfish

The Azure Damselfish is one of the most beloved of the Damselfish Types, because of their bold and beautiful coloration and personalities.

2. Blue Devil Damselfish

The Blue Devil Damselfish is one of the most popular species. As their name suggests, they can be a bit of a devil in your community tank, claiming a large footprint of space in your tank as its own, and “defending it” vigorously.

They are omnivores that will occasionally pick at some algae in the tank, but they should also be fed a varied diet that includes meaty foods and algae-based preparations.

In some varieties, the male’s tail is actually orange.

3. Yellowtail Damselfish

The Yellowtail Damselfish is blessed with the reputation of being one of the least aggressive damselfish, which, along with their gorgeous coloration, hardy constitution and inexpensive price tag, makes them one of the most popular saltwater fish species.

Are yellow tail damselfish reef safe?

Yellow tail Damselfish are reef safe. They will peacefully interact with the corals, clams, and mobile invertebrates in your tank. They are also one of the more peaceful species of damselfish, which makes them less likely to squabble with the other fish in your reef tank, although some individuals will still be territorial.

4. Blue Sapphire (Springer’s) Damselfish

Are Springer damsels aggressive?

Spring damsels are listed as “peaceful” on Saltwaterfish.com and Liveaquaria.com, but as is the case with most damselfish species, they will likely be aggressive towards peaceful, timid fish and other damselfish, including clownfish. My recommendation is to consider them semi-aggressive and avoid mixing with peaceful species.

5. Talbot’s Damselfish

Talbot’s Damselfish is relatively mild-mannered, by damselfish standards, although there are frequent reports of certain individuals being quite territorial, despite their reputation. They come from the Indo-Pacific reefs and need a varied diet to remain healthy, like most Damsels.

6. Rolland’s Damselfish

Rolland’s Damselfish is an attractive damselfish type with more subdued coloration and markings compared with the other show-offs in the Chrysiptera genus.

7. Princess Damselfish

The Princess Damselfish is perhaps the most strikingly beautiful of all the damselfish types on this list. Their coloration reminds me of the much coveted Flameback Angelfish. If I was going to risk aggression in my tank to add a Damselfish, it would be to add this beauty to my tank.

8. Blue and Gold Damselfish (Goldbelly)

It is remarkable to me to see that there is a Damselfish type with just about any configuration of blue and gold that you can imagine. The Gold belly, or Blue and Gold Damselfish has a gold belly, as the name implies, that starts with the pectoral fin and extends all the way to the tail.

9. Neon Damselfish (Allen’s Damselfish)

Allen’s Damselfish, which also somehow secured the name Neon Damselfish (they all seem a bit Neon to me), has brilliant blue coloration on the majority of its body, with gold highlights on the ventral, anal and caudal finds, interspersed with blue flecks. They are quite attractive, and also semi-aggressive, just like the rest of the fish on this list.

10. Lemon Damselfish

If you are interested in having a small, but mighty burst of yellow in your tank, the somewhat overlooked Lemon Damselfish is an attractive damselfish type.

11. Ambon Damselfish

12. Pink Smith Damselfish

Having a little fun with the image above, but the Pink Smith Damselfish (also popularly called Demoiselle) is a relatively subtly colored beauty.

13. Regal Damselfish

14. Three stripe Damselfish (Humbug)

The Three Stripe Damselfish has one of the BEST alternate common names–Humbug! They look very similar to the Four Stripe Damselfish, except with no stripe on the tail.

These beautiful fish are often sold as tiny juvenile fish that are commissioned to be the first fish in a new saltwater tank. This causes problems later on, due to their aggressive dispositions.

15. Four stripe Damselfish

The Four stripe Damselfish is so named because of the three bold stripes on the body of the fish, as well as the fourth stripe of black that covers the tail-end of the caudal fin. Hah! Tail end!. Go ahead, scroll back up, you’ll see. They look almost identical to the Three stripe except for the black tail.

This is a popular and common damselfish type, but they are not always a great choice for the peaceful community tank due to their aggression.

16. Two Stripe Damselfish

17. Three Spot Domino Damselfish

The Three Spot Domino Damselfish is one of the larger damsels on this list. They should be kept in a tank that is 55-gallons or larger, because they will reach ~5.5 inches as adults. As you can see in the image, they do like to live amongst the tentacles of anemones, just like clownfish.

There is some risk that any/all damselfish will eat invertebrates small enough to swallow. That risk increases with larger species, like the Domino.

18. Bluefin Damselfish

Topping the charts at a full 7-inch adult length, the substantial Bluefin Damselfish is one of the largest and most aggressive type of damselfish you will encounter at your local fish store. You likely won’t see a full-sized adult, but rather the tiny, cute, seemingly harmless 1.5-2 inch juvenile. But these fish grow up to be quite large in size and are not afraid to throw around their weight.

With that said, they are hardy, reef safe, and easy to care for.

Unnecessary commentary from the author (me): I find it interesting that the common name for Neoglyphidodon melas is the Bluefin Damselfish. They clearly do have blue highlights to their ventral fins, which is a distinguishing feature, but I’m not sure it captures the essence of the fish.

19. Ternate Damselfish

20. Blue Velvet Damselfish

The Blue Velvet Damselfish is a commonly stocked and attractive fish as a juvenile that grows to be very large (6 inches/15 cm) as an adult. They are also one of the less fortunate fish, that like me, becomes less attractive as an adult than as a juvenile :).

The blue neon/velvet stripes fade to become a predominantly drab/dark colored and aggressively dispositioned large fish.

Buyer beware.

21. Jewel Damselfish

Hard to believe we can come to the bottom of the list of popular damselfish types and just be getting to the Jewel Damselfish, but that is a testament to how diverse and attractive these beauties are. The Jewel is another one of the larger fish on this list, growing to about 6 inches/15 cm in total length as adults.

They are reef safe towards corals, but may be a problem if you stock small invertebrates, as they are opportunistic hunters.

Which is the most peaceful damselfish type?

Based on reputation and personal experience, the most peaceful damselfish types are likely Springer’s, Yellowtail, and the Azure damselfish, which also makes them the least aggressive. However, there is no definitive or authoritative way to rank the aggressiveness of different fish species.

You may notice that these are all members of the Chrysiptera genus, a group of relatively smaller and directionally more peaceful type of damselfish.

There is an ancient Saltwater Aquarium Blog proverb passed down from my elders that states:

What are the most aggressive damselfish types?

The most aggressive damselfish types are the Blue Devil, Two stripe, Three stripe, Three spot, Four stripe, Bluefin, Velvet, and Jewel Damselfish.

If you’re thinking…that’s a lot of species…you are right. Damselfish can be quite aggressive.

Interestingly enough, Saltwater Aquarium Blog elders also passed down a proverb about this:

Can you mix different damselfish?

Most damselfish are aggressive or semi-aggressive saltwater fish. Mixing different damselfish, or even two or more of the same type of damselfish can be tricky, but it is possible. To do so, here are 5 tips to help:

1. Add them to the quarantine tank and display tank at the same time
2. Combine similarly-sized individuals (both current size and anticipated adult size)
3. Choose similarly aggressive species
4. Add 3 or more from each species
5. Add cleaner fish and shrimp to the tank

1. Add damselfish to the tank at the same time to disperse aggression

Damselfish aggression is generally thought to be in response to a natural tendency to protect and defend their territory from interlopers. If you add the damsels at different times, the incumbent fish will have already established a territory and will therefore be more aggressive in protecting it.

When the fish are all introduced at the same time, they establish a hierarchy and divide up the available space. Assuming there is enough room for everyone, the end result should be a more balanced distribution of territory.

2. Choose similarly sized fish to avoid bullying

The smallest Damselfish species grow only to about 2 inches (5 cm) in le.ngth as fully grown adults, while others grow to 6 or 7 inches (15.2 or 17.8 cm)!

Damselfish can sometimes be tank bullies. Just like all bullies, their first option is to pick on someone they perceive as weaker than themselves. One of the quickest ways to create that imbalance is to mix damselfish species that are different sizes today.

You will also want to be careful not to mix damselfish species that will be dramatically different sizes in a few months. Even though they may all be cute ~1.5 inch juveniles in the tank at your local fish store, mixing a 7-inch Bluefin Damselfish with a ~2-3 inch Azure Damselfish will result in a David vs. Goliath situation before long.

3. Choose similarly aggressive species to strive for balanced aggression

Attempting to manage aggression in an aquarium is a bit like fighting fire with fire. Your goal is to achieve balance. So if you want to mix damselfish species, you will likely have the greatest success if you try to mix damsels with similar aggressive dispositions. Don’t mix semi-aggressive varieties with semi-peaceful.

4. Choose larger, odd numbers of fish to strive for dispersion of aggression

One interesting aspect of aggression exerted by aggressive fish species is that it tends to be relatively constant. As long as the aggressor has energy, feels safe, and can see the threat, they will likely attack and defend.

So one of the strategies to help manage aggression in fish is to have many, similarly aggressive fish all together. When that occurs, there is less ‘picking’ on a weaker individual, and instead, the aggression is spread out on several other targets. Since we also carefully selected those “targets” to also be similarly aggressive, they, too, have their own targets, and so on.

In that way, you create a web of dispersed aggression, which helps prevent any one or two fish from becoming targeted so much that they become sick, injured, or worse.

5. Add cleaner fish and shrimp to the tank

There was a scientific study many years ago demonstrating that cleaner fish reduce aggression in a saltwater aquarium. Essentially, the more the fish in the study got cleaned by the cleaner wrasse, the less aggression they displayed–not just because of the ‘time outs’ but it somehow soothed the savage underwater beasts.

I can’t say for sure whether or not that specific insight could be successfully applied to this situation, but cleaner fish and shrimp are awesome…so why not give it a try?

Do damsels get ich?

Ich, “ick” or “white spot disease,” is caused by a parasite that attacks the gills and skin of saltwater aquarium fish, including damsels and damselfish.

Why is my damsel turning white? 

If you see your damsel turning white at night, looking more pale than during the day, this is a normal, routine event, as part of preparation for rest. If your damsel is turning white during the day, it could be a symptom of stress, illness, or malnourishment.

If your damsel is turning white, you should try to remove the cause of the stress and see if you can improve the nutritional quality of the food.

Can damselfish live with clownfish?

Damselfish and clownfish are likely to be aggressive towards each other and should not live together in the same saltwater tank, unless you have a very large aquarium.

Are damselfish hardy?

Damselfish are some of the most hardy saltwater fish available for a marine aquarium. They are tolerant of less-than-perfect water parameters, eager to eat the majority of available foods and most live a long time. Damselfish are often one of the first fish added to a new saltwater tank because they are so hardy.

Caution is advised though, because most damselfish species can be moderately aggressive, which can cause problems when you try to add your second, third and subsequent fish. So although their constitution is hardy, making them an ideal starter fish, their aggressive behavior is not.

Can damselfish change color?

Damselfish can change color and will change color to a lighter/paler shade at night and to a darker shade when stressed or scared. Springer’s damselfish will turn from blue to almost black when stressed and trying to avoid a predator.

Are damselfish jumpers?

All saltwater fish are somewhat susceptible to jumping out of an aquarium with no lid if they feel sufficiently startled but damselfish a moderate risk of being a “jumper,” similar to that of a clownfish. Dartfish, wrasses, and jawfish are notorious jumpers.

References

Michael, Scott W. Marine Fishes: 500+ Essential-to-Know Aquarium Species. TFH Publications, Inc. Neptune City, NJ 2001

Live Aquaria