Bicolor Damselfish Identification Guide

Key identification features

• Front half of the body and head pale white to light grey
• Rear half of the body and tail dark brown to blackish, with a fairly sharp vertical boundary between the two zones
• Small, oval, laterally compressed body
• Small size, typically 3-4 inches (7-10 cm)
• Juveniles show the same two-tone split but with more contrast than adults

Common look-alikes

• Threespot damselfish juveniles are bright yellow with blue spots rather than a plain pale-and-dark split, and adults turn uniformly dark brown without a pale front half.
• Cocoa damselfish is a fairly uniform yellowish-brown over the whole body, lacking the sharp two-tone break of the bicolor damselfish.
• Dusky damselfish is a more uniform grey-brown throughout, without the clean pale head seen on bicolor damselfish.

Where you'll see one

Bicolor damselfish are common on shallow Caribbean and western Atlantic reefs, from Florida through the Bahamas and Caribbean islands to Brazil. They are highly territorial, guarding small patches of algae turf on coral rubble or dead coral heads and aggressively chasing off other fish that intrude.