Indian vagabond butterflyfish

The Indian Vagabond Butterflyfish, Chaetodon decussatus, is a species of butterflyfish (family Chaetodontidae). It is found in the Indo-West Pacific, from the Maldives via India, Sri Lanka and the Andaman Sea to the westernmost portion of the Indonesian archipelago.[2]

Growing to a maximum of 20 cm (nearly 8 in) long, it is found on rich coral reefs and also on rubble and rocky areas. The monogamous adults swim in pairs and may be territorial and aggressive to other Chaetodon; juveniles are solitary. The Indian Vagabond Butterflyfish feeds largely on algae and coral polyps. They are oviparous.[2]

It belongs to the large subgenus Rabdophorus which might warrant recognition as a distinct genus. In this group, it almost certainly is a rather close relative of the Threadfin Butterflyfish (C. auriga) and the Vagabond Butterflyfish (C. vagabundus). C. decussatus might be closer to the Threadfin Butterflyfish than to the common Vagabond Butterflyfish; as C. vagabundus has yielded abnormal DNA sequence data this is hard to say however. The C. auriga species group shares the characteristic pattern of two areas of ascending and descending oblique lines; species differ conspicuously in hindpart coloration.[3][4]