The twospined angelfish has a basic dark purplish-blue body. This is marked with irregular orange vertical bars on its flanks. The dorsal, caudal and anal fins have a bright blue margin.[3] The dorsal fin contains 14 spines and 17–18 soft rays while the anal fin has 3 spines and 17–19 soft rays. This species attains a maximum total length of 10 centimetres (3.9 in).[2]
The twospined angelfish is found at depths of 5 to 50 metres (16 to 164 ft) in coral reefs within lagoons, rubble patches and drop offs, being commonest around drop offs.[1] They live in small social groups consisting of a single male and a few females. They are protogynous hermaphrodites and the most dominant of the females in a group will change sex to become male if the existing male dies or disappears.[3] This species feeds on algae and detritus.[4]
Systematics
The twospined angelfish was first formally described in 1869 by the German-born British ichthyologist and herpetologist Albert Günther (1830–1914) with the type locality given as Ambon Island, Indonesia.[5] In some classifications it is placed in the subgenus Centropyge.[6]
Utilisation
The twospined angelfish is frequently found in the aquarium trade.[1]
