Ctenochaetus strigosus

A fish belonging to the family Acanthuridae, origin: Indonesia, the Philippines, the Australian Great Barrier Reef, the Okinawa Islands and the Hawaiian Islands.

A hardy fish with a peaceful temperament, but it cannot live with others of its kind or other Acanthurids. Oval in shape, laterally compressed and elongated; the head is characterised by a concave forehead; the mouth is prominent, small and has fleshy lips needed to graze on algae on the rocks. Like all surgeonfish, on the caudal fin it has the classic "scalpels", which are very sharp bony structures used to defend itself from rivals or natural predators. In the wild it can be seen grazing on algae in the shallow waters of lagoon areas or close to the reef cliff. The adult livery is a very bright dark blue; on the head there are numerous turquoise dots, and on the body there are lengthwise lines; the fin has the same base colour; the dorsal and anal fins are edged with turquoise; the pectoral fins are dark yellow with orange shading.

To keep it in a tank, excellent water quality is needed; in optimal conditions it is an animal resistant to disease. It suffers from low pH and excessive concentrations of nitrate and phosphate; it loves a strong flow, preferably alternating and intermittent. When stressed it is prone to attacks of Oodinium and to fungal skin infections.

Given its size, it must be kept in large tanks from 500 litres upwards, essential to have adequate room for swimming with crevices among the rocks to take refuge in.

Once introduced and during acclimatisation it accepts food with difficulty, but it will be seen grazing on the algae on the rocks in the tank. Once settled in it is omnivorous: in fact it can be given frozen food (Artemia, chironomus, mysis), dry foods and sheets of Nori seaweed. It does not refuse vegetables such as lettuce or boiled spinach.

Species sheet by Massimo Ramognino and photo by Emanuele Casati