Adults of this species can grow up to 10 centimetres (3.9 in) at maximum length. They have 12 dorsal rays, 9 to 11 soft dorsal rays, 2 anal spines, and 9 to 11 anal soft rays on their fins. It is a blue green fish. When they are breeding, males turn more yellowish.

How big do blue chromis get?

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.

Are Blue Chromis aggressive?

Chromis are aggressive and are bully's. They will chase other fish out of the aquarium.