About Chelmonops truncatus (Kner, 1859)
Chelmonops truncatus closely resembles its relative the Western talma (C. curiosus). The main difference between the two is that the dorsal fin of C. truncatus is truncated, while the western species has a long filament on its dorsal fin. The fins and dark body bands of C. truncatus are often tinged vinaceous, which gives them a dark red appearance in some types of light. Like other butterflyfishes, juvenile C. truncatus have a clear ocellus on the dorsal fin. This marking smudges and becomes less visible as the fish matures. The smooth profile of the rear section of the dorsal fin is more noticeable in younger fish, and this part of the fin grows slightly elongated in adults. In adult C. truncatus, the rear margin of the soft dorsal and anal fins is almost vertical, while juvenile fins are more rounded. This species reaches a maximum total length of 22 centimetres, or 8.7 inches. C. truncatus is endemic to south-eastern Australia, where its range extends from Double Island Point in southern Queensland south to around Jervis Bay in New South Wales. This species lives in coastal bays and estuaries, along deep rocky walls. Adults are typically found in pairs, while juveniles are often found alone. Their diet is made up of small crustaceans, worms, and filamentous algae. Breeding pairs of C. truncatus defend their territories.
