Green Chromis: Care Guide, Reef Compatibility, Diet and More

Green Chromis Care Guide, Reef Compatibility, Diet and More Banner

The Green Chromis is by far one of the most popular saltwater fish amongst fish-keeping hobbyists.

Its dazzling color and flamboyant personality are all reasons why it has remained so popular for over 30 years.

Whilst many members of the damselfish family are known for their aggression, this particular family member is known for its calm and playful nature.

In this complete guide we have covered everything you need to know about keeping a Green Chromis, including; its natural habitat, what and when to feed them, how to care for them, compatibility with other fish, and much more…

If you are short on time you can read our quick facts table below for a brief overview.

Green Chromis Facts & Overview

Green Chromis

Care Level:Easy
Color:Pale green
Lifespan:Over 8 years
Size:Up to 4 inches
Minimum Tank Size:30 gallons
Tank Setup:Marine: coral

The Green Chromis, also known as Blue Green Chromis (and scientifically as Chromis viridis), is a hugely popular saltwater fish.

In the wild, they will be found in the Indo-Pacific region and spend large amounts of their time in protected areas such as lagoons and corals.

You will typically find them in large shoals as they are peaceful fish.

They will grow up to 4” long and are known for their vibrant shades of green. They have a slender oval-shaped body with a distinctive forked tail.

A shoal of these swimming through your aquarium will provide flashes of green as the lighting hits their body.

Its popularity is due to its peaceful manner, beautiful appearance, and relative ease to care for (regardless of the keepers’ experience). In addition to this, it can also make a great community fish and is reef compatible (more on this later).

If you are planning to keep a group of them you must make sure you keep at least 6; this helps to prevent occasional bullying. As Green Chromis are social fish it is not recommended that you keep them on their own.

In an aquarium, you will find that they are one of the most active swimmers spending the majority of their time in the middle water column.

Overall, because of their affordability, stunning coloration, and ease to keep, they are a great addition to any aquarium.


Green Chromis ApperanceRenowned for their beauty, Green Chromis can vary in color from light blue through to pale green.

They have a compact body with a glorious forked tail giving it a striking appearance. This is with the exception of matured males, who, during mating, turn into a yellow color with a black tail.

You should expect a Green Chromis raised in an aquarium to grow up to 3” with wild ones growing up to 4”. As a result of this, you can keep them in smaller aquariums (more on this later).

Then Green Chromis is commonly confused with a Black Axil Chromis (Chromis atripectoralis). The Black Axil has a slightly longer and slender body. It also has a black blotch on its inner pectoral fin; hence the name.

Habitat and Tank Requirements

Green Chromis Schoal
Shoal of Green Chromis

The Green Chromis is a saltwater fish found in the shallow reefs of the South Pacific and Indo-Pacific Ocean.

You will find them in large shoals spending the majority of their time in coral reefs and lagoons. They swim in shallow waters of around 1 meter but have been found at depths of up to 12 meters.

Like always, we recommend that the aquarium you place your Green Chromis in matches their natural habitat as closely as possible.

As they spend a large amount of their time in coral formations, you should make sure that their aquarium is full of coral; they love to live, play and hide in it. If you’re starting out try corals like Acropora.

You will notice that in an aquarium the Blue Green Chromis will swim in all levels of the water column, but you will mainly find them in the middle; they are active swimmers and will be one of the ‘busier’ fish in your aquarium.

If you’re keeping a couple of them; a smaller aquarium of 30 gallons will work fine. However, if you are going to keep a shoal; then a minimum of 60 gallons is needed.

Tank Conditions

Your aquarium water conditions should be as followed:

The water temperature should be between 72.0 to 82.0°F, with a pH range of 8.1-8.4 and a specific gravity of 1.023 to 1.025.

As previously mentioned, you should have plenty of coral within the tank and ideally some planted sections with algae for them to graze on.

Unlike many freshwater fish, water movement isn’t particularly important for saltwater fish. However, if anything, you should ensure that the current isn’t too fast.

Tank-Tip: Aquarium Maintenance

As mentioned in the breed overview section, these damselfish fish as very hardy and recommend to beginners for this reason.

With this being said you still need to take care with water changes and poor water quality; this can result in diseases.

  • If you have a smaller tank (30 gallons) you should perform 15% water changes fortnightly.
  • If you have a larger tank (60 gallons and up) for a shoal then you can perform a 30% cycle monthly.


This type of Damselfish is an omnivore, meaning it will eat both animal and plant matter.

In the wild, they are somewhat of a scavenger; eating larva, mysid shrimp, copepods, zooplankton, phytoplankton, and algae.

They have even been known to eat fish eggs that haven’t yet hatched.

As they each such a wide variety of foods, you must ensure you offer them a varied diet in your tank.

Fortunately, Chromis are fantastic eaters and will eat just about anything you give them, including frozen food, flakes, pellets, meat, and vegetables.

For frozen food, you can feed them Krill and Mysis shrimp. You can also use a liquid vitamin which will help their body color stay vibrant. You can supplement this with an herbivore flake and fresh finely cut vegetables.

In terms of how often to feed them, it depends on the size of your aquarium. Ideally, you should feed them 3 times a day.

If you have a smaller tank I would recommend feeding them once a day. Feeding them too often in a small aquarium is a common beginner’s mistake, and will result in poor water quality as rotting food alters the pH levels.

Whereas, if you have a larger aquarium (60+ gallons), you can stick to the ideal 3 times per day feeding routine.

Typical Behavior

The Green Chromis is a very active fish and loves to swim. It’s even more mesmerizing to watch in a shoal as they swim throughout the aquarium’s corals in synchronization.

Whilst the majority of damsels are known for their aggression, the Green Chromis is the exception.

They are known for their reasonably peaceful temperament and can be kept with lots of other community fish. If you are planning to keep them in a school make sure to keep at least 6 (more on this later).

If you observe them closely, the majority of the time you will see them swimming in the middle sections of the water column. They are fast swimmers who will play with each other if kept in a community tank.

They will swim amongst the coral and will generally ‘sleep’ within the coral so make sure to have plenty around.

The only exception to this is that you will notice when spawning they can turn aggressive to one another, so if you’re intending to breed them be careful.

Compatibility with other Fish

Green Chromis CompatibilityThe Green Chromis can make a great community fish; they can even create a school with their own species (more on this later).

As mentioned above, they are reef compatible and you can keep them with corals.

You will want to keep them with other friendly community fish such as Basslets, Butterflies, and Blennies.

You can keep them with other somewhat aggressive fish like tangs, however, you should always bear in mind the larger fish rule…

If your Green Chromis is being bullied it will spend nearly all its time right in the top corner of the tank. This is when you need to take action; either remove it or the bully.

Keeping Green Chromis Together

One of the most impressive things you can see in a home aquarium is a school of Green Chromis.

You will see vibrant flashes of greens and blue as they swim in the mid-upper water column.

To have a healthy school of Green Chromis you need to have at least six.

When you first add them to the tank you will notice they form a hierarchy very quickly; like a pecking order for chickens. The most dominant Green Chromis will be at the top of the hierarchy with the weakest, most submissive, at the bottom.

You need to keep at least six together to prevent the ‘alpha’ from bullying each individual fish too much; it helps spread out the aggression.

Is the Green Chromis Right For Your Aquarium?

Unlike many members of the damselfish family, the Green Chromis is a peaceful fish that would make a great addition to a community tank.

This will be one of the busier fishes in your tank and you should make sure to feed it a varied diet. You can also keep them in a school which produces a spectacular variety of greens.

You should make sure that their aquarium has plenty of coral as they love to swim and sleep near it.

Overall, it is a resilient fish that is easy to care for and would make the ideal starter fish for a beginner.

Do you keep Green Chromis? Let us know about them in the comments section below…

About Robert 468 Articles
Robert Woods is the creator of FishKeeping World, a third-generation fish keeper, and a graduate in animal welfare and behavior. He is also a proud member of the Association of Zoos and Aquariums, the Marine Aquarium Societies of North America, and the Nature Conservancy.


  1. Brandon says:

    Can you keep the blue/green chromis together with the Weber’s chromis? I would ideally like to put 3 of each in my tank, but don’t know if I should or not. Also, should I put them in all together?

    • Fishkeeping World says:

      I don’t have any experience of keeping these fish together, but I can’t think of any reasons not to. Make sure you keep at least 6 together, and keep a close eye on them when you first add them. I would put them all in together. Let me know how you get on. Thanks, Robert

      • Sam and Stephanie says:

        We have a tank with an azure damsel, a gold tail damsel, a Bangi cardinal, true percolate, a flame hawk and a gramma in a 55:gallon tank. If we add a green chromosome, will any of our other fish bully it?
        Thank you!

  2. brody says:

    I was wondering if I could keep two Green Chromis together in a community tank or should I only put one in.

    • Fishkeeping World says:

      Hi Brody, ideally these fish need to be kept singularly or in a group of at least 6 to prevent bullying. Thanks, Robert

  3. Scott says:

    These fish aren’t as peaceful as mentioned. They can be aggressive to their own types and will kill off the weak ones. Some people have trouble keeping a shoal of them. Once they settle in, they are mostly peaceful. They do have their territorial spats after settled in.

  4. Diana says:

    I have a fairly newly established aquarium and put in a group of 5 Chromis (prior to reading this). One has developed a black tail. He doesn’t seem unwell or bullied – is eating and swimming fine. Any advice appreciated as I am a complete beginner obsessed by my fish !

  5. Bob Knuth says:

    I noticed red spots by the nose of one of the fish but he seems to eat well? I test and test my water everything is perfect I do regular partial water changes making sure the temperature and salinity is the same. I seem to lose fish regularly. I’ve kept freshwater fish my whole life. I’ve done everything I can think of but still loose fish occasionally? I never have issues with freshwater fish?

  6. Rosie Conte says:

    I had a Green Chromis for about 8 month and I lost him the other day. He was very active and ate well but I fed my fish once a day in the evening. I feed heavy due to NPS corals. I added rock flower anemone few days ago and he died after. I’m getting the feedback that RFA didn’t have anything to do with his death but seems too coincidental. Could he have died because he needs to be fed 3x a day? If so, he survived 8 months in my tank without any problem…

  7. Percy says:

    I’m keeping a Chromish Fish in 3 gallon tank but they didn’t survive..please teach me how to take care of it?

  8. Jamie says:

    I’ve got a 60 gallon with 3 Pajama Cardinals, 2 snowflake clowns, Lawnmower Blenny, Yellow Watchman Goby and a Green Mandarin. I was hoping to add the Blue/Green Black Axil Chromis, but don’t have space for 6 to keep in a school. Is there a chormis like the Lightning double bar that can be kept in 3’s? or is that not possible? Is it possible to have one of 3 different types, like 1 Blue/Green, 1 Green and 1 Blue without issue? Really looking to add some movement and color to the aquarium. I do also have coral so they have to be reef safe. Thanks!

  9. Jamie says:

    I’ve got a 60 gallon reef tank with 2 clowns, 3 Pajama, Lawnmower Blenny, Watchman Goby and a green Mandarin. I see a healthy school is 6 which I don’t have room for. Is it possible to add 1 of different kinds? Like 1 Blue/Green, 1 Green and 1 Blue? Are there any Chromis that do well in 3’s like the Lightning Double Bar?

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