Blue Green Chromis Care: The Complete Guide

The Blue Green Chromis is one of our favorite saltwater species. Their high activity level and color-driven beauty make them a joy to observe.

And we’re not alone.

These fish are quite popular in the saltwater fishkeeping community, and it seems like the number of people getting them is increasing at a rapid pace.

While this is well-deserved, it’s important to understand how to keep these fish happy and healthy. And whenever a species becomes trendy, a lot of misinformation follows.

And that’s why we made this guide. It will teach you everything you need to know about Blue Green Chromis care, so you can be sure you’re doing things the right way.

Table of Contents

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Species Summary

Considered one of the easier saltwater fish to take care of, the Blue Green Chromis (scientific name: Chromis viridis) is perfect for beginners and novice fishkeepers alike. This fish is also commonly referred to as the Green Chromis.

A Blue Green Chromis swimming in a saltwater tank

Thanks to their beautiful appearance, these fish will add a lot to the aesthetic of your tank. Additionally, their active lifestyle makes them interesting and fun to watch!

The Blue Green Chromis has a very wide distribution and are found throughout the Indo-Pacific region. The species inhabits lagoons and reefs ranging from Madagascar to the Philippines to Hawaii.

Docile and easy-going, these saltwater fish can make wonderful additions to multi-species tanks. They do exceptionally well in coral-laden tanks, allowing you to create a beautiful marine ecosystem.


The average lifespan of a Blue Green Chromis is somewhere between 8 and 15 years. When healthy, it’s not unreasonable to assume that they’ll live for more than a decade.

However, it’s worth noting that this lifespan is only possible with proper care. Like all saltwater fish, this species will suffer if kept in poor living conditions. It’s important to keep their environment well-maintained to prevent them from perishing earlier than expected.


Take one look at the Blue Green Chromis and it’s not hard to see why this species is so beloved in the saltwater aquarium community.

Their bodies are covered in iridescent hues of blue and green (hence the name). The green is a light apple shade while the vibrant blue shimmers in the light. This makes watching the Green Chromis swim around the tank a wonderful display of color.

This species also has no discernible markings on its body. As a result, their stunning coloration is the star of the show!

The fins are all transparent and feature tiny rays. The dorsal fin is expansive, stretching from behind the head to just shy of the caudal fins. The tail fin has a distinct forked shape.

Male Green Chromis

Author Note: There aren’t any major differences between males and females of this species. However, males will often turn yellow and develop a black tail around mating time. This is actually one of the easiest ways to figure out their gender.

Average Size

These saltwater fish aren’t very large. The average size of a Blue Green Chromis is three to four inches long when fully grown. 

With that being said, they do grow quite a bit from the time most owners first purchase them. When sold, these fish can be as small as half an inch in length!

Generally, those raised in captivity stay closer to three inches long. Specimens in the wild are the ones that tend to reach four inches.

Blue Green Chromis Care

Blue Green Chromis care is quite easy, as this species is considered to be one of the lowest maintenance saltwater fish around. Great for beginners, these fish are hardy and can tolerate a generous range of conditions.

That said, the Green Chromis can only reach its full potential with top-notch care. It should always be your goal to provide them with perfect conditions anyway, so this shouldn’t be much of a problem!

Here are some general care guidelines you need to follow:

Tank Size

Blue Green Chromis aren’t huge, but you will still need a sizable tank. This species prefers to live in groups, so you must be prepared to accommodate multiple fish. Not only that, but they need plenty of space to swim and explore their environment.

This species needs a minimum tank size of 30 gallons to stay healthy. That’s enough space for a small group of fish. If you plan on creating a multi-species tank, bigger is always better.

Author Note: A cramped tank will only create unnecessary stress and make it more difficult to maintain water conditions. A tank that’s too small will also increase the possibility of aggression within the school

Water Parameters

This species adapts well to life in captivity when it comes to water parameters. In the wild, they come from a wide range of environments.

Usually, they stick to shallower waters. However, they can be found at depths of 12 meters too! Inhabiting coral-filled lagoons, it’s best to replicate the conditions of their natural environment as closely as possible.

Stick to these water parameters for the best results:

  • Water temperature: 72°F to 82°F (around 75°F to 78°F is the ideal range)
  • pH levels: 8.1 to 8.4
  • Water hardness: 8 to 12 dKH
  • Specific gravity: 1.020 to 1.025 (the middle of this range is best)

It’s important to invest in a reliable and accurate water testing kit to ensure that these parameters are being met. It’s one of the most important pieces of equipment you have, so get something good!

Setting Up The Rest Of Their Tank

In the wild, Blue Green Chromis stay in the protection of reefs and rocky outcrops. Unlike some other saltwater fish, this species will not harm coral.

They do very well with Acropora coral head. However, pretty much type will do fine.

In addition to coral, implement plenty of live rock. Some planted areas with algae are good for grazing too!

Make sure to keep the middle and top of the tank fairly open. Blue Green Chromis will take advantage of all the open swimming space they can get!

It’s important to invest in a powerful filtration system. Green Chromis can be sensitive to ammonia and nitrates. When kept in larger groups the water can sour pretty quickly, so a solid filtration system will keep things in check.

Author Note: Current isn’t too important to this species. They don’t seem to have any major preference. Just make sure that the current isn’t too extreme to ensure their safety.

Potential Diseases To Watch Out For

No saltwater fish is immune to disease. The good news is that there are no major illnesses that target the Blue Green Chromis specifically. Thanks to their hardy nature, these fish usually stay pretty healthy.

That said, poor living conditions can result in some issues. One of the most common diseases these fish suffer from is crypt, which is basically marine ich. Interestingly enough. Blue Green Chromis are often the first in a community tank to show symptoms.

One healthy Chromis viridis searching for some food

Crypt is a contagious disease that primarily targets the gills of the Green Chromis. If left untreated, it can cause a secondary infection called Uronema disease. Both can be fatal, so make sure that you quarantine sick fish and provide treatment as soon as possible.

Blue Green Chromis are also susceptible to marine velvet, which is caused by a dinoflagellate parasite.

To avoid any of these diseases, do your best to maintain a healthy habitat within the tank. Monitor water parameters regularly to ensure that they’re always in an acceptable range.

Blue Green Chromis Food & Diet

Blue Green Chromis are omnivores by nature. In the wild, they will regularly feed on a wide range of food sources.

They spend a lot of time scavenging. Food like like larvae, tiny shrimp, and algae are all on the menu!

So it will come as no surprise to know that these fish will thrive on a varied diet when kept in captivity. You can provide dry flakes or pellets as their main source of nutrition, but it’s always good to supplement with nutrient-rich snacks as well.

These fish love to eat live foods that are high in protein. Provide Krill, Mysis shrimp, and brine shrimp occasionally. To help bring out their natural color, you can also look out for vitamin supplements or foods targeted toward their appearance.

Author Note: Feed your Blue Green Chromis a few small meals throughout the day and provide them with enough food that they can eat in a couple of minutes. Make sure to remove any leftovers to prevent the water conditions from deteriorating.

Behavior & Temperament

Technically speaking, Blue Green Chromis are part of the damselfish family. However, unlike damselfish, they are not aggressive.

This species is very peaceful and prefers to stay out of skirmishes. When kept in a group, the fish can develop a pecking order, but fights and aggressive behavior can easily be kept to a minimum if you keep them in a large tank.

Your Blue Gren Chromis will spend most of their time swimming throughout the tank in a shoaling group (many call this a school). They like to stay within the middle of the water column, but they are not scared to venture to the bottom or skim the surface!

They are powerful swimmers that like to dart back and forth, creating a splash of color in your tank. This is another reason why it’s so important to provide ample swimming space. You’ll get the enjoyment of watching them explore every inch of the tank and coral.

Tank Mates

As mentioned earlier, these fish prefer to stay in groups. At the very least, you should have six or seven Blue Green Chromis together. Many aquarists like to keep them in odd-numbered groups.

A group will help the fish feel more confident and prevent stress.

Beyond tank mates of the same species, Blue Green Chromis are compatible with many other peaceful saltwater species. You don’t have to worry about problematic behavior from the fish.

But there are some animals you need to watch out for.

In general, you should avoid keeping them with large fish or eels. They will easily overpower the Green Chromis and eat them for lunch! It’s best to stick to other peaceful species of a similar size.

Try these tank mates on for size:


Blue Green Chromis can breed in captivity, but they need just the right conditions. The most important thing is safety.

These fish will never spawn if there are predatory fish that could eat their eggs.

In a predatory-free environment, males will often turn yellow. They can get a bit more territorial and aggressive around breeding time, so keep an eye out for trouble.

The male will prepare for spawning by building a nest in the substrate. One or more females will then deposit eggs in the nest. After that’s done, the male fertilizes them.

Males will watch and care for the eggs the entire time. He may eat some eggs, but they’re usually unfertilized or dead.

Eggs will hatch in two or three days. But, the baby fry will stay in the vulnerable larval stage for up to 47 days! To help with survival rates, you can transfer the hatched fry to a separate nursery tank.            

Wrapping Up

As you can see, there’s a lot to like about this species. From their lovely colors to their spunky attitude, you’ll have quite a fun time owning them!

And to make things even better, keeping them in a home aquarium is a piece of cake. Blue Green Chromis care is as simple as it gets.

We hope you learned a lot from this care guide and feel ready to purchase this species for yourself. You’ll be happy you did!

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