What do they eat?
Damsel fish have a diet of Plankton, tiny crustaceans but what they really enjoy is the algae that grows on coral. Damsel fish select one piece of coral and they eat or weed the algae on the coral. This is called farming. They protect that one piece of coral from any intruders so that way the algae has time to grow and also so that they protect the coral from any unwanted visiters like other fish that eat coral. Damsel fish are very territorial so they will fearlessly attack any fish that comes near it's territory, even divers. The coral and the damsel fish therefore have a symbiotic relationship by working together to keep eachother alive. The damsel fish protects the coral from being eaten by other fish, and the coral provides the damsel fish with algae which the damselfish eats.