The Blacktail Butterflyfish 

The black-tailed butterflyfish (Chaetodon austriacus), also known as blacktail butterflyfish or exquisite butterflyfish, is a species of butterflyfish, beloging to the Actinopterygii class, Periformes order, Chaetodontidae family.
Chaetodon austriacus Blacktail butterflyfish Pesce Farfalla Austriaco
The species is native to the Red Sea and southern Oman.  As of 2011 it has been present on the Mediterranea coast of Israel, evidently as a Lessepsian migrant via the Suez Canal. Chaetodon austriacus Blacktail butterflyfish Pesce Farfalla Austriaco

The black-tailed butterflyfish is up to 14 cm long and is orange with thin, curved black stripes. Its anal fin and tail are black. The body of juveniles is whiter above with white bands on the tail. The melon butterflyfish (C. trifasciatus) and the oval butterflyfish (C. lunulatus) are similar in coloration but have less black on the caudal and anal fins.

Black-tailed butterflyfishes tend to be found in coral-rich areas between 0.5 and 20 m deep, on seaward reef or in lagoons or bays. Adults are generally found in pairs patrolling a territory or range while juveniles are found among coral branches. This species grazes on coral polyps and sea anemone tentacles.

Together with the melon and oval butterflyfishes and probably also the somewhat aberrant Arabian butterflyfish (C. melapterus), the blacktail butterflyfish makes up the subgenus Corallochaetodon. They are probably quite close to the subgenus called Citharoedus (that name is a junior homonym of a mollusc genus), which contains for example the scrawled butterflyfish (C. meyeri). Like that group, they might be separated in Megaprotodon if the genus Chaetodon is split up.

(extract from Wikipedia)