Blue/Green Chromis Care Guide

Blue/Green Chromis overview and appearance

The Blue/Green Chromis (Chromis Viridis) is a wonderful saltwater fish to keep in both fish only tanks and reef environments. They are very popular with beginner hobbyists as they are a tough fish that is easy to keep. Both beginners and experts love to keep Chromis and they make an excellent choice for many tanks.

The Chromis is a damselfish that is very active in the aquarium and loves to swim in the middle to upper parts of the tank. They are a schooling fish and should be kept in groups of 5-6 or more. Many damselfish are known for their aggressive behavior but the Chromis is not one of them. They are very peaceful and don’t bother other livestock in the tank.

The Blue/Green Chromis are very colorful. Yes, you guessed it- blue and green. They generally have a pale green color mixed with a light blue tint. It’s a very nice combination. The males can sometimes have a yellow color with a black tail when mating. It is easily recognized by the sharply forked tail and tail fin which allows them to move quickly and dart if startled. They are a quick-moving fish.

Blue/Green Chromis care chart


The Blue/Green Chromis can be found in the shallow reefs of the South Pacific and Indo-Pacific Ocean. They commonly swim in large shoals of about 100. You can keep them individually in the aquarium but they will do better in groups. 5-6 or more are recommended.

They love to swim around corals and rock formations. They are very active in their natural habitat and they will act the same way in your tank. They will normally swim in the upper part of your tank but it’s common to see them in the middle as well.

Temperament and behavior

You won’t run into any aggression issues or bad temperament from the Chromis. They are mild-mannered and playful, they not known to be a pest or bother other tankmates. Other fish won’t feel threatened by them either. They are also reef safe so don’t worry about having corals in your aquarium. They won’t pick or bother corals.

Also, they are safe with invertebrates meaning they are no threat to snails, shrimps, or any others. They are about the best-behaved, low-risk fish you can have for a home aquarium.


Blue/Green Chromis are omnivorous and will eat plant and animal matter. In their natural habitat, they will eat copepods, shrimp larvae, and amphipods. They are also known to eat fish eggs. In the aquarium, they should be fed a good quality mix of flake, pellet, and frozen foods like shrimp and krill. NLS makes a great saltwater pellet and flake food that Chromis will eat.

They are not picky and will gladly accept any food that falls within their diet. They should be fed a few small feedings per day. It’s important not to overfeed as this can lead to a variety of issues.

Image credit U.S Fish and wildlife service

Tank requirements and setup

If you plan to keep Chromis in your aquarium, you should try to mimic their natural environment the best you can. You should have lots of rock formations and hiding places with plenty of coral for them to swim around. Corals provide comfort and give them places to sleep. They enjoy being around all types of corals.

If you only have a single fish or just a few, then a 30-gallon tank size will be big enough. If you plan to have a school of 6 or more, then a 55-gallon or bigger is recommended.

Chromis don’t require high water flow, but you will notice they like to swim into the current and don’t mind being pushed around by the wavemakers.

Your tank temperature should be kept at a constant level around 79F, PH 8.1-8.3, and salinity 1.025 SG.

Although the Blue/Green Chromis is a tough fish, you should strive to maintain good water conditions. Aim for water changes on a scheduled basis of about 15% for smaller tanks and 30% monthly for larger tanks.


Like many fish, in order for breeding to be successful, you will need pristine water conditions. Although breeding the Chromis is not overly common in the home aquarium, it has been done.


The Chromis is susceptible to diseases when living in poor water conditions. It’s important to test your water quality on a regular basis and take note of any patterns or irregularities or signs of stress of the fish. Bullying can cause stress leading to disease which can be passed among others.

A common disease is Marine ich or White spot disease. Also, Marine velvet is possible. These are all a parasite which if caught early, can be treated. It’s important to quarantine new fish and have a hospital tank ready if your Chromis becomes sick.

Availability and cost

Another great thing about the Blue/Green Chromis is the fact they are commonly available at most local saltwater fish shops. They are also very affordable at around $8-10 each. So for less than $60, you should be able to find a nice school of 6 Chromis that will be stunning in your tank.

Should you consider buying Blue/Green Chromis for your tank?

Yes, these are one of the most commonly found saltwater fish in the hobby. They make great tankmates, are peaceful and are a joy to watch. They are constantly active, love to swim around corals and are easy to care for. They are great for beginners and advanced hobbyists alike.

Thanks for reading!