The Half-blue Damselfish, also known as the Azure Damselfish, is a two-tone, darting marine fish. The front portion of the body is bright blue. The posterior portion, anal fin, and tail are yellow. There is a species variation in the amount of yellow on the body of the fish. (Some call C. parasema the Azure Damselfish, however, in the aquarium trade, the Azure Damselfish is considered to be C. hemicyanea.)

A 50 gallon or larger aquarium is suitable for a small group of Half-blue Damselfish.

In the aquarium, the Half-blue Damselfish can be fed a varied diet of meaty items, vitamin-enriched shrimp, herbivore flakes, and frozen preparations.