A clownfish (Amphiprion bicinctus) sheltering in its host anemone (Heteractis magnifica): an excellent example of symbiosis. Egyptian Red Sea.

A clownfish (Amphiprion percula) in its host anemone (Heteractis magnifica). Clownfish are excellent subjects for close-up photography as they tend to shelter in their environment if approached, rather then flee elsewhere. This is the result of the remarkable symbiotic relationship between them and sea anemones. The fish are immune to the anemone's stinging nematocysts and, when they feel threatened, seek refuge amongst the tentacles.