Blue Green Chromis: Fish Species Profile

Characteristics, Origin, and Helpful Information for Hobbyists

Blue green chromis fish with light blue and silvery scales

The Spruce / Adrienne Legault

A member of damselfish family, the Blue Green Chromis fish (Chromis viridis) is a peaceful inhabitant of saltwater aquariums. With an iridescent, light blue-green colored body, Blue Green Chromis are gorgeous fish to keep in a saltwater aquarium and prefer being kept in a small school of 3 to 5 individuals. The Blue Green Chromis is reef safe (it won't eat the reef invertebrates) and gets along with most other fish. 

The Blue Green Chromis is a relatively inexpensive, easy to care for, and hardy saltwater species. Although a smaller reef species, Blue Green Chromis fish are active and inquisitive, so they are generally out and about in the tank. For all these reasons, the Blue Green Chromis is a great choice for beginners looking to add color and flash to a saltwater aquarium. 

Species Overview

Common Names: Blue Green Chromis, Green Chromis, Blue-Green Reef Chromis

Scientific Name: Chromis viridis

Adult Size: 3 inches

Life Expectancy: 8 to 12 years


Family Pomacentridae
Origin Indo-Pacific
Social Peaceful
Tank Level All levels
Minimum Tank Size 30 gallons
Diet Omnivore
Breeding Egglayer
Care Easy
pH 8.1 to 8.3
Hardness 8 to 12 dGH
Temperature 77 to 79 F (25 to 26 C)

Origin and Distribution

The Blue Green Chromis fish is found in tropical waters of the Pacific Ocean, east of the Philippines, New Guinea and eastern Australia. Blue Green Chromis live in coral reef areas and lagoons where they prefer to group into a school.

Colors and Markings

The color of the Blue Green Chromis is a pale, shimmery light blue-green with an iridescent overlay. Male Blue Green Chromis will sometimes change colors during spawning—turning pale yellow—when they are ready to begin building a nest. Some individuals may have darker markings on their fins. Typically, the juvenile Blue Green Chromis that are available for purchase at fish stores range from one to two inches, and can grow up to three inches long.


A relatively peaceful species, Blue Green Chromis should be kept in a small school. They can be kept with most other saltwater fish excluding large predatory fish that might eat the smaller Blue Green Chromis. When planning what fish to add to an aquarium, always add the most peaceful fish species first, working your way up to the most aggressive fish species you plan to keep. This helps limit fighting amongst fish due to territory issues. Be sure to check that your water chemistry values are appropriate for the different species before mixing fish as well.

Blue Green Chromis may snack on tiny, juvenile invertebrates like shrimp and crabs, but will not bother larger invertebrates. These fish leave corals alone, so this species does well in reef tanks as well as fish only tanks.

Looking for some recommendations? Check out the below species as good companions for the Blue Green Chromis:

Clownfish (Amphiprion ocellaris)
Clownfish (Amphiprion ocellaris)

Morten Thomsen/Getty Images

Yellow Tang (Zebrasoma flavescens)
Yellow Tang (Zebrasoma flavescens)

Santiago Urquijo/Getty Images

Blue tang (Paracanthurus hepatus)
Blue tang (Paracanthurus hepatus)

Charlotte Blenijenberg/Getty Images

Blue Green Chromis Habitat and Care

Like most damselfish, Blue Green Chromis are quite hardy, making them a good choice for newer aquarists. Unlike other species of damselfish, Blue Green Chromis are relatively docile, and get along well with many other reef species. They are active swimmers, so when keeping Blue Green Chromis in reef tanks, make sure your décor allows plenty of space for swimming in the middle to top of the tank. Blue Green Chromis do like having a place to rest or hide, so ensure they have a small cave or crack to call their own if they choose to take a break.

A small group of Blue Green Chromis will tend to school together or may join up with other small, schooling reef fishes. Even though Blue Green Chromis are small, if you wish to keep a school, your tank should be large enough to provide plenty of swimming space. Overcrowding a saltwater aquarium contributes to territory spats between fish, poor water quality and poor fish health.

Blue Green Chromis Diet and Feeding 

Blue Green Chromis are omnivores, which means they eat both meaty and plant foods. For most reef tanks, feeding a varied diet is the best way to provide complete, balanced nutrition. Feed a mix of meaty and herbivore foods, including flakes, pellets and frozen foods.

Feed your fish a few small meals per day, taking care not to overfeed. Saltwater fish are natural foragers, eating very small amounts throughout the day. Once a day, large feedings are not the best option for maintaining a healthy digestive system. A surplus of uneaten food in your saltwater aquarium will contribute to poor water quality and unwanted marine algae growth. Always watch your fish closely during feeding time to ensure all of your fish are getting enough to eat, not being bullied, and are not injured or sick.

Gender Differences

Male and female Blue Green Chromis fish do not have reliable discernable physical differences. However, mature males may change color during spawning, turning a lighter yellow, but this may not always occur.

Breeding of the Blue Green Chromis Fish

Blue Green Chromis will sometimes breed in captivity if aquarium conditions are ideal and the eggs and fry are kept safe. It is best to move a breeding pair of individuals to a separate breeding tank in order to ensure survival of the offspring. A separate aquarium also allows you to manipulate temperature and light levels, key factors to stimulate fish to breed.

Blue Green Chromis males will prepare a nest in the sand bed into which more than one female will lay a large number of eggs. During external fertilization, males will spray their sperm on the eggs, then tend to the nest and protect the eggs until they hatch just a few days later. Unfertilized eggs or those that do not hatch are usually eaten by the male.

Once the Chromis eggs hatch, remove the adults to prevent them from eating their young. Fry require a diet high in fat and protein in order to ensure proper development.

More Pet Fish Species and Further Research 

If you like the Blue Green Chromis fish, and you are interested in similar fish species for your saltwater aquarium, read up on:

Check out additional fish species profiles for more information on other saltwater fish.