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Zebrasoma is a genus of marine fish composed of seven species of pointed-snout, disc-like bodied, sail-like finned, single peduncular-spined fishes. Zebrasoma are usually placid community fish, many forming large groups or shoals, although fiercely territorial against other tangs or similar shaped or coloured fish in an aquarium setting. Zebrasoma like all Acanthuridae have a forward-facing spine on each side of the caudal peduncle (visible as a short, horizontal stripe on the base of the tail in the above picture). This spine, apart from terminating in a point, has angular edges that result in a scalpel-like sharpness along its length also. When alarmed, tangs can erect the spines sideways and slash at their opponent with rapid sideways movements of the tail. In some surgeons, the spines are fixed in the offensive position. The family name reflects this nature, meaning, literally, "Thorn Tail".
Care must be exercised by aquarists should it be necessary to handle these fish. An encounter with even a small, frightened tang can result in a wound requiring stitches. Large specimens are quite capable of inflicting deep, life-threatening injuries - an adult Sohal Surgeon may have spines 4cm long, quite capable of reaching the femoral arteries of an unfortunate diver. There is some evidence to support the claim that in this fish in particular, the spines are either venom tipped or coated with epithelial cells (as in some urchins) which further complicate any injury. Colloquially described as a "Fish with a flick-knife", due mainly to their calm nature, such attacks on humans are rare. Aggression in tangs is usually confined to presenting their tails to a would be predator or attacker and is usually minimal against conspecifics, some however have noticed the purple tang to be more aggressive than most zebrasoma. Most aggression however is due to territory disputes.
Zebrasoma are also very sensitive to disease in the home aquarium. However, if the fish is feed enough algae though and the aquarium is properly maintained disease should not be a problem. It is usually necessary to quarantine the animals using copper sulfate or formalin for a period of around 2 weeks. Adults range from 15-40cm (6-15 in.) in length and most grow quickly even in aquariums. When considering a tang for an aquarium it is important to consider the size to which these fish can grow. Larger species can grow to 40cm (15 in.) and require swimming room and hiding places. Many also suggest adding aggressive tangs to the aquarium last as they are territorial and may fight and possibly kill other fish.
Zebrasoma primarily graze on macroalgae, such as caulerpa and gracilias, although they have been observed in an aquarium setting to eat meat-based fish foods. A popular technique for aquarists, is to grow macroalgae in a sump or refugium. This technique not only is economically beneficial, but serves to promote enhanced water quality through nitrate absorption. The growth of the algae can then be controlled by feeding it to the tang.