The the Yellowback Anthias (Pseudanthias evansi) is also known as the Goldback Anthias, Goldback Basslet and the Purple Wreckfish. They are abundant on the East African coast in some areas and scarce in others.
The Yellowback Anthias has a fairly typical Anthias shape but is less robust and smaller than most other species of Anthias only growing up to 8cm in length. They exhibit sexual dimorphism with the females being smaller than the male. Females as seen below are predominantly violet with a yellow back and caudal fin. The caudal fin is deeply forked with long thin edges. There is a light purple line through the eye. The male pictured above is larger than the female and has yellow dots on the upper body.
YELLOWBACK ANTHIAS IN THE WILD
The Yellowback Anthias is not very common on the mainland coast and are only found on the edge of the deeper reefs. Usually they shoal in very large numbers of up to several thousand fish and make a very attractive sight especially in clean water with good light. They are relatively easy to get close to and as long as one does not make any sudden moves they will generally mill around without going into hiding. They often shoal with other species of Anthias.
Yellowback Anthias are found on the East African coast from Kenya to South Africa across to Christmas Island including the Andaman sea and western Sumatra. In Tanzanian waters they are seen only on the deeper reefs at around 15 plus meters downwards, mainly on walls or steep coral rich slopes that drop off into deeper waters.
The main diet of the Yellowback Anthias is plankton. They usually shoal close to the substrate on walls or steep drop offs and make darts into the water table to feed on plankton.
Yellowback Anthias are found in haremic groups of a male and several females. Spawning takes place between couples into the water table. If the male for some reason disappears then the dominant female will turn into a male. The large shoals are comprised of a large number of haremic groups.
Yellowback Anthias are seen in the trade. They are best kept in small groups , if there is no male in the group the largest female will change into a male. They feed in the open water above the substrate and will be happier if they have some swimming room in the tank along with some good hiding places. They may jump so a well sealed tank is a good idea. They are not easy to keep and are recommended for experienced aquarists only.
YELLOWBACK ANTHIAS CLASSIFICATION