Dictionary of Ichthyology  

symbiosis = the living together of two species to their mutual benefit, e.g. luminescent bacteria in photophores of certain fishes; hydroid polyps which grow on and camouflage Minous; and anemone fish (Amphiprion) with sea anemones, where the territorial fish protects the sea anemone from other fish that try to eat it and the sea anemone's nematocysts or stinging cells protects the fish against its predators (mucus on the anemone fish protects it from the nematocysts). See also commensalism.

Aquarium photo of Amphiprion ocellaris. Photograph by Brian W. Coad.

Canadian Museum of Nature
www.briancoad.com