Bicolor Damselfish

A small, fiercely territorial damselfish, dark on the front half of its body and pale yellow-white on the rear, that farms a patch of filamentous algae on the reef and defends it aggressively against grazers many times its own size — including divers who linger too close. One of the most common and conspicuous small fish on Caribbean reefs.

Coral rubble and reef structure at all depths

Territorial algae farmer; aggressively defends its patch against intruders of any size