Blue Green Chromis Fish (Chromis viridis): Fish Species Profile

Although the Blue Green Chromis fish (Chromis viridis) belongs to the damselfish family (a group of fish generally known for being somewhat aggressive in saltwater fish tanks), the Chromis is an extremely peaceful inhabitant of saltwater fish tanks. With its iridescent, light blue-green colored body, Blue Green Chromis fish are a gorgeous fish to keep in a saltwater fish tank. They enjoy swimming the length of the tank, which makes for a shimmering addition of color and movement as they dart about, especially when you keep a school of three or more other Blue Green Chromis. The Blue Green Chromis fish is reef safe, bothering neither corals nor invertebrates, and gets along with most other fish (although Blue Green Chromis should not be kept with large, predatory fish, including eels, which could easily make a meal out of your Chromis). 

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

The Blue Green Chromis fish is found in tropical and subtropical waters throughout the Indian Ocean and Pacific Ocean, including the Red Sea, Madagascar, Sri Lanka, Indonesia, the Philippines, Polynesia and the Hawaiian Islands, just to name a few. Blue Green Chromis live in coral reef areas and lagoons where they school in groups.

The color of the Blue Green Chromis is it’s crowning glory: a pale, shimmery light blue-green with no discernable markings. Male Blue Green Chromis will sometimes change colors during spawning—turning pale yellow—when they are ready to begin building a nest. Blue Green Chromis can grow to about four inches long, but juvenile Blue Green Chromis available for purchase range from about half an inch to about three inches long.

A peaceful species, Blue Green Chromis can be kept with most other 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. Blue Green Chromis do not bother invertebrates like shrimp and crabs, and these fish leave corals alone, so this species does well in reef tanks as well as fish only tanks.

Like most damselfish, Blue Green Chromis fish are quite hardy, making them a good choice for new aquarists. Unlike most damselfish, Blue Green Chromis are docile, preferring to stay out of any skirmishes amongst other fish in the tank. The enjoy swimming, so when keeping Blue Green Chromis Blue Green Chromis in reef tanks, make sure your rockscape allows plenty of space for swimming in the middle to top of the tank. A group of Blue Green Chromis will school together. A small school of Blue Green Chromis darting about the tanks is a dazzling sight to see, making this species a great addition to any saltwater fish tank. Some aquarists recommend keeping odd numbers of schooling fish like Blue Green Chromis (for instance, three, five, seven or nine fish). 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 fish tank contributes to territory spats between fish, poor water quality and poor fish health.

Blue Green Chromis fish are omnivores, which means they eat both meaty and vegetariasn foods. However, the diet should primarily contain meaty foods like mysis shrimp, krill and brine shrimp. Feed a variety of mostly meaty foods and plus some herbivore foods. Food options for feeding Blue Green Chromis fish may include flakes, pellets and frozen foods. Some aquarists like to soak fish foods in a vitamin supplement made specifically for marine fish to bolster fish health and possibly to help keep the Blue Green Chromis fish’s color vibrant. Feed your Blue Green Chromis fish a few small meals per day, taking care not to overfeed. A surplus of uneaten food in your saltwater fish tank will contribute to poor water quality and unwanted marine algae growth.

Male and female Blue Green Chromis fish do not have discernable physical differences. However, mature males will change color during spawning, turning a light yellow. 

Blue Green Chromis fish will sometimes breed in captivity if tank conditions are ideal and there are no predators in the tank to eat the eggs. Blue Green Chromis fish males will prepare a nest in the sand bed into which more than one female will lay a large number of eggs. The males fertilize 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.

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

• Fishfish Goby
• Flame Angelfish
• Flame Hawkfish
• Yellow Tang

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