Fish species of the genera Amphiprion and Premnas (Perciformes: Pomacentridae) as well as various crustaceans seek protection from predators among the tentacles of sea anemones, where they live essentially unharmed from stinging by the host's nematocysts. The mucous coats of anemonefish and crustaceans have been suggested as mechanisms that prevent the discharge of the nematocysts upon contact. Whereas some fish species seem to produce their own protecting mucous coating, others may acquire mucus from the sea anemone during an acclimation period, as crustaceans do. Whether the natural or acquired mucus layers contain components that inhibit nematocyst discharge or simply lack compounds stimulating the stinging cell's exocytosis is still unknown.