Holacanthus africanus is found in clear water over rocky reefs at depths between 1 and 40 metres. Holocanthus africanus is differently coloured in juveniles and adults. The juvenile West African angelfish (West African angel pure blue) is usually 3-4cm. It has a dark blue body with thin light blue vertical bars on either side of the eye with a yellow caudal fin and lips and with the mid body area having a wide vertical pale blue band.
The diet of the West African Angelfish should include vegetable matter like marine algae, spirulina. Feeds on sea urchins, worms, mussels, clams, hydroids, crabs, crustaceans, and algae, chopped frozen fish, shrimps and also marine flakes food. The juvenile West African angelfish feeds also on brine shrimps.