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Green Chromis Overview, Care, Tank Setup & Breeding

The Green Chromis has gained widespread attention because of its energetic persona and dazzling appearance. They belong to the Damselfish, infamous for their aggression, but the green-shaded Chromis is the polar opposite. It is docile, playful, and gets along with most fish.

Green Chromis are ideal for fishkeepers with some experience in caring for saltwater fish. If you want to keep one in your marine tank, here is our in-depth guide to help you care for it.

Species Overview

Level of CareBeginner to Intermediary
TemperamentExtremely peaceful
AppearanceA shade of green with light bluish hues
Life Expectancy8 years or more if properly taken care of
SizeReach a size of 4 inches maximum
DietOmnivorous species
Tank Size30 gallons
Tank EnvironmentMarine tank with a compatible reef and friendly fish
Tank MatesVery peaceful with other community fish

Green Chromis (Scientific name: Chromis Viridis) originate from lagoons under tropical and subtropical waters throughout the Pacific Ocean and the Indian Ocean, including Madagascar, Indonesia, and the Red Sea.

They thrive in groups because of their docile nature. This reef fish prefers to live in saltwater and spends most of its time in areas such as corals and lagoons.

It would help if you strived to mimic an oceanic ambiance with ocean rocks, caves, reefs, sea plants, and corals for the comfort of your Green Chromis.

They are very hardy and will be relatively easy to keep. They do well in most aquariums and don’t require special apparatus or lighting.


Aquarists can’t get enough of their blue-green appearance, which has no discernable markings. The male Green Chromis may change his colors during the breeding season, turning a pale yellow color before building a nest.

The average Green Chromis size is 3 inches in captivity, while the wild ones grow up to 4 inches. It allows beginners to keep them in smaller tanks.

They is sometimes confused with the Black Axil Chromis, which has a slender, slightly longer body. It also features a black spot on its pectoral fin, hence the name.

The Blue-Green Chromis has a prominent forked tail, which allows it to stand out in a tank. The tail may change color in mature males when they are ready to build their nest.

Behavior & Temperament

The Green Chromis is known for its exciting personality and loves to swim around at breakneck speeds.

They’re very active and mesmerizing to watch in groups while they glide around the tank’s corals in sync with each other. While the vast majority of Damsel species are known for their aggressive temperaments, these are the exception to the norm.

They are reasonably passive and can be kept with other community fish. These guys prefer to live in shoals of at least six or more other Green Chromis.

If you observe them, they tend to spend most of their time occupying the middle portion of the tank (choose tank mates that swim in the tank’s top and bottom areas).

You can also see them playing with each other as they playfully dart across the tank. When tired, they sleep inside the coral, making sure they have lots of space to move around.

Their hostile nature takes over when it’s breeding season, though – so watch them closely during this time because they will turn aggressive toward one another and fight.

Common Variants of Chromis

Brown Chromis

Brown chromis

Brown Chromis are usually found in the Western Atlantic Ocean and the ocean near Ascension Island. As their name suggests, they are dark brown, which is in stark contrast to the Blue-Green Chromis.

Lemon Chromis

Lemon chromis

Lemon Chromis are found near the Indonesian oceans. They’re the same as Green Chromis except, they sport a yellow-green appearance. They are only 3 inches in size, making them ideal for beginners.

Black Axil Chromis

Black-axil chromis

They have the same color and pattern as Green Chromis, but they have a slender shaped body by comparison. They are found in the South Pacific Ocean and thrive in the middle column of the tank. Aquarists like them because of their docile nature and small size. They are omnivorous and will eat both vegetables and meat.

Half and Half Chromis

Group of half-and-half chromis

These fish are known as Half and Half Chromis because they combine two colors in equal parts – half brown and half white.

It is a rare color combination for freshwater species and has been a subject of much attention in the last few years. They are usually found in the Red Sea in regions near Australia. They typically scavenge for food in the wild, making them ideal tank cleaners.

Orange Lined Chromis

Two orange-line chromis

This species of Chromis has main light orange lines on its body with a pale blue appearance. Adults will change their color to brown with a white-shaded tail. They are native to the Indian Ocean and are relatively rare in most markets. They are small, peaceful in size, and attractive, three features that make aquarists love any fish species.

Tank Mates

The peaceful Green Chromis can share the same space with most fish, excluding large territorial fish that may mistake the smaller Green Chromis as prey.

When adding tank mates to the marine aquarium, you should always start by adding the most peaceful fish first, working your way up to the most aggressive fish species that make your Chromis’s life miserable.

It is an efficient way to keep the in-fighting down and also prevents territorial disputes. Green Chromis mostly leaves invertebrates like crabs and shrimp alone and do not bother corals, so this species thrives well in the reef and fish-only tanks.

Of course, the most impressive thing to see in your marine aquarium is a shoal of Green Chromis. They’ll flash bright blues and greens at you as they dart from one area of the tank to another.

Green Chromis are an intelligent species and quickly form hierarchies within their school, almost like a pecking order for chickens. Dominant ones will be at the top of the hierarchy while the weakest ones will be at the bottom.

Having six in the same space is essential if you want to keep aggression from ‘alpha’ Chromis at bay. There’s power in numbers, and it also minimizes their aggression.

Below is our list of the friendliest saltwater tank mates for Green Chromis:

Ideal Tank Requirements

Green Chromis occupy the middle portion of the tank and don’t like to swim on the tank’s surface. Their tank should mimic their natural habitat, surrounded by sea plants, rock works, caves, Acropora, and various other corals. It will make them comfortable.

Do not keep the tank overcrowded if you want them to feel safe in the tank. The ideal size is about 30 gallons for this peaceful 4” fish.

However, it is recommended to keep around 6 Green Chromis in a tank to prevent in-fighting and bullying. If you decide to keep 6 of them, consider upgrading to a 60-gallon tank. It is an active swimmer and requires tons of space to move in a tank.

The most important part of the tank is the water, of course. Should keep it at around 73 to 81° Fahrenheit. Must maintain the pH value of the tank slightly alkaline 8.2 to 8.4. Keep the water hardness between 9 to 11 dGH.

To clean the tank and all the objects within it, use liquid soap. The best way to clean the corners of the tank is to use a soft brush. It is recommended to clean the tank once every month.

Cleaning doesn’t necessarily mean taking out the entire water from the aquarium. It’s sufficient to partially change 25% of the water without harming the Green Chromis or upsetting its habitat.

If you feel the need to clean out the entire tank, then remove all the fish using a fishnet and keep them in a separate tank during the cleaning process. It will be needed when the tank degrades in quality.

Tank Setup

With just a tiny bit of research and planning, you can build a thriving ecosystem that’s entertaining to watch and makes a great addition to your home.

Saltwater fish may sometimes visit the bottom of the tank to rest on the substrate. For this reason, it is advisable to keep a sandy substrate to minimize the damage done to the fish. Chromis is a little shy and prefers to hide when stressed out. Please provide them with lots of caves and rocks in the marine aquarium, so they don’t feel threatened.

There aren’t many unique requirements for Green Chromis fish in terms of lighting because they’re not very fond of lights in their home.

Install an advanced filter that can maintain the water’s quality to keep your Green Chromis healthy and happy.

Consider tucking a few aquatic plants in the aquarium to create a natural-looking marine tank and make them look good. Here is our round-up of 5 low-maintenance plants:

Red Mangrove Propagule

Red Mangrove trees are found in most tropical oceans around the world. They help to lower the nitrate levels in a tank but require iron supplements to do so. With proper lighting, they should take hold of your tank pretty soon.


Since they’re found in most oceans worldwide, the Halimeda plant looks good in most marine tanks. It is attractive to look at the unusual leaves that look like coins stacked together like a chain. Some people also call them ‘money plants’ because of their shape.

Green Finger Algae

These plants are great for most saltwater tanks because of their unusual bright green color and lush, dense appearance. They are hardy and add a bit of variety to most aquariums.

Red Gracilaria Algae

If you’re encountering difficulty keeping balance in your aquarium, you may want to add the Gracilaria.

This plant effectively fights off algae growth and can even be fed to herbivorous fish in the tank. All you have to do is anchor it to the tank using a firm surface such as a rock so it can quickly gain stability.

Food & Diet

Group of green chromis hiding in coral

Because they are an omnivorous species, the green Chromis diet includes both plants and animals. They’re known for scavenging after their food in the wild, including eating larvae, copepods, zooplankton, algae, and phytoplankton.

They also like to eat fish eggs that haven’t yet hatched. Since they’re not such picky eaters, you can feed them a varied diet.

They will eat pellets, meat, flakes, frozen food, and vegetables. They love eating Mysis shrimp and Krill. If you want them to retain their color, use some liquid vitamins to ensure they stay bright and vibrant. Supplement their regular diet with fresh vegetables finely chopped into little pieces or buy some vegetarian flake.

It is recommended to feed them at least three times a day if you’ve got a large tank. For a smaller tank, you can provide them once a day only. Abstain from overfeeding your Green Chromis because this will alter the water’s quality and contribute to their early demise.

Breeding Green Chromis

Green chromis pair

Green Chromis are easy for beginners to breed but will turn aggressive as their wild nature takes over during the spawning season.

It is recommended to separate them in a special breeding tank to prevent other fish harm. Green Chromis is a hardy species and will survive the initial shock of being transported to a new tank.

The tank conditions need to be ideal to initiate breeding, and there must be no predators in the tank to eat the eggs.

During the breeding process, the male will create a nest to secure a place for his eggs. The male and female pair will engage in a mating ritual where they dance in rapid swimming patterns and fin movements.

Males will turn much darker during this process. The female will then lay a large number of eggs that will then get fertilized by males. Unlike most fish, Green Chromis parents will tend to their nest and protect their eggs until they hatch a few days later.

The unfertilized eggs will get eaten by males. Once the fry hatch, it becomes essential to save them from other fish breeds by keeping them in a separate tank with their parents.

Common Diseases and Dangers

Their immune systems are relatively robust, but Green Chromis are reasonably susceptible to the following diseases:

  • Marine ich
  • Marine velvet
  • Fungal infections
  • Viral diseases
  • White spot

You can prevent most diseases with a varied diet, right water conditions, and good hygiene. If you suspect your Green Chromis of any of the above diseases, take them to a vet for recommendations on the best course of action.

The tank should be cleaned twice a month to maintain proper hygiene. Use a fish net to hold them very carefully, so they don’t feel stressed out or scared.

Where to Buy?

Green Chromis for sale can be abundantly found in most marine pet stores, online stores, and online forums. If you want to search for rarer breeds, look at online forums for specialist breeders known for carrying them.

Most marine fish are generally expensive, and the Green Chromis is no exception. Most pet stores will sell them for about $9. Before buying them, inspect for any signs of disease. Their appearance should match the description, and they should be reasonably active. If the Green Chromis are unusually quiet in the tank, it may indicate disease and illness signs.

Final Thoughts

Unlike most Damsel family species, the Green Chromis is very peaceful and perfect for beginners new to saltwater fish keeping. Just make sure to provide them with a varied diet.

Bonus points if you can provide them with a 60-gallon tank. They’re fairly robust and will make your tank stand out.

The average Green Chromis lifespan is about eight years or more, so they will reward you for taking care of them.