Family : Pomacanthidae
Text © Giuseppe Mazza
English translation by Mario Beltramini
The Twospined angelfish (Centropyge bispinosa Günther, 1860), called also Coral beauty angel, belongs to the class of the Actinopterygii, the ray-finned fishes, to the order of Perciformes, to the family of Pomacanthidae and to the genus Centropyge which is the most numerous of the family with 32 species.
The etymology of Centropyge comes from the Greek “kέντρον” (kentron) = sting and “πυγή” (pyg) = rear with reference to the showy spine of the operculum bent towards the tail.
The name of the species bispinosa comes from the Latin “bis” = twice and “spinosus” = spiny with reference to the long spine it has on the two opercula.
It is present in the tropical waters of the Indo-Pacific.
We find it, as an indication, in South Africa, in East Africa and in Madagascar, but is absent in the Red Sea. Then at the Seychelles, the Andaman and the Maldives, in Malaysia, Indonesia, New Guinea, Australia, Micronesia, Philippines, Taiwan and China up to the southern part of Japan with the islands of Ryukyu and Ogasawara.
Eastwards, it has colonized Vanuatu, Samoa, Tonga, Tahiti and Tuamotu.
Southwards, after New Caledonia, it has reached Lord Howe.
It lives among madrepores and the corals, in the lagoons, in the submerged grasslands and on the cliffs of the reefs, usually between 5 and 45 m of depth.
It can reach the 10 cm of length, but rarely exceeds the 8 cm.
The body is flat, oval, with the dorsal and the anal fins wide and rounded at the apex. The first counts 14 spiny rays and 16-18 soft; the second 3 spines and 17-19 unarmed rays. The pectoral fins have 15-17 soft rays, the ventral ones do not have spines and are pointed, and the caudal is more or less truncated.
The mouth, small but with big lips, has several brush-like teeth.
The livery, much variable, is dark in its whole and is very mimetic.
The central part has usually some irregular vertical dark orange stripes on a more or less flaming orange background and more or less restricted by the dark violet blue of the remainder of the body. The margin of the fins is electric blue, as well as the spine of the operculum and the snout, but the ventral fins are orange and the pectoral ones are yellowish. Sometimes, also the vertical stripes are blue, and there are individuals decidedly unusual, wholly blue, orange or yellow.
The specimens living in deep waters, where the habitat colours are less bright, are usually paler. The juveniles, which in the angelfishes have often very different drawings and colours, in this species are, since the beginning, similar to the adults.
The twospined angelfish nourishes of algae, polyps of madrepores, sponges and ascidians. It is a hermaphrodite protogynous species, that is, with females changing sex while ageing. During the reproductive time, small harems take form with a dominating male and 3-7 females. The fecundation takes place in surface. The eggs and the larvae are pelagic. They live, for three days, of the yolk sac then of plankton, and after a post-larval stage, around the two months, they resemble to the adults.
The Centropyge bispinosa often hybridizes with Centropyge shepardi and there are nurseries for the aquaria market offering various variants of colour.
In nature, the populations may double in less than 15 months and the fishing vulnerability index of the species stands among the lowest ones: only 10 on a scale of 100.
Holacanthus bispinosus Günther, 1860; Centropyge bispinosus Günther, 1860.