Chromis cyanea, known by the common names blue reef chromis and blue chromis, is a fish from the western Atlantic Ocean that is occasionally kept in marine aquariums.
This is a small marine fish that reaches 15 centimetres (5.9 in) in length. It is typically blue with a black margin on its back.
The blue chromis are bought in groups of odd numbers. It should be kept in a tank of at least 30 gallons. It is reef-safe and will not harm fish of similar size, though it may harass smaller fish if not fed enough.