This is a tropical reef fish belonging to the diverse dottyback family, which includes over 100 species in a wide variety of patterns and colours. The dark dottyback is one of the plainest dottybacks, being entirely reddish-black in colour.
They reach eight centimetres in length, and have a characteristically elongated body. Like clownfish, all dottyback species are hermaphrodites, although in this case, the male is larger than the female. The males inhabit a cave or crevice in the reef, which they entice females to enter using an intricate mating dance. Females lay up to 1,000 eggs which are subsequently fertilised by the male, who guards and aerates the eggs for the duration of their incubation. Dark dottybacks feed on zooplankton and small crustaceans.
More striking in appearance than the dark dottyback, the Dutoit’s dottyback is dark yellow in colour with black and electric blue stripes on its face and along its dorsal ridge. Its tail fin is dark red or pink, and edged with electric blue.
Dutoit’s dottybacks grow up to nine centimetres in length, and are found in the Western Indian Ocean from Pakistan to just south of Durban, South Africa. They favour shallow rocky and coral reefs, and the males defend their cave or crevice aggressively. After mating, the female lays eggs in an empty shell, where they are guarded by the male until they hatch. Like all dottybacks, Dutoit’s dottybacks are protandrous hermaphrodites, which means that they are born male, but can change to become female as circumstances demand.