Acanthurus olivaceus

When older these fish become more greyish in colour and the orange markings on the shoulder will be more noticeable. The tail also becomes more lyre shaped.

Some species in the Acanthurus genus mimic various Angelfish as juvenile, since predatory fish know that small Angelfish are hard to catch. They are therefore difficult to identify from a picture of adult fish.

Acanthurus species often place higher demands on: tank size, surroundings and water quality, than fish in the genus Zebrasoma.

Surgeonfish (Acanthuridae) live primarily of different types of algae, making it a popular choice for coral aquariums, as they help to keep the aquarium algae free.

Most Surgeonfish have a scalpel by the caudal fin, used to defend themselves. It can cause some deep lacerations, so pay attention if the fish start to fight and when handling the fish.

When in the aquarium, they will spend most of their time swimming around and nibbling the algae from the stones. Surgeonfish will rarely irritate corals or invertebrates. Large Palettes/Blue tangs can be an exception.

The Surgeonfish are not typically aggressive towards other types of fish. If more Surgeonfish are added to the aquarium, they will establish a hierarchy. It is best to add the most aggressive species last and to ensure that there are sufficient hiding places, as they prefer to have their own individual sleeping area.

If multiple aggressive species are added to the same aquarium, one runs the risk of one of them dying due to stress. One must therefore be cautious about adding multiple Acanthurus species or Zebrasoma xanthurum into the same aquarium. A combination of the different genera will normally get along well, although the more aggressive species can still be challenging.