Photographer: Paul Osmond
(see this users gallery)
A bright red male Spinecheek Anemonefish (Premnas biaculeatus) within his host sea anemone on the Tulamben Slopes dive site in Tulamben Bay in Bali, Indonesia.
The female of this species is larger, and generally display a much muted red coloration than the male. They are also tremendously territorial and their aggressive displays are well worth observing.
The smaller male, as can be seen here, are much brighter and much smaller than the large female.Tulamben Slopes is one of the premier muck diving sites in the world, featuring black sand slopes that are some of the richest in the world.