
Banded Butterflyfish
Chaetodon striatus
Chaetodon lunula

The raccoon butterflyfish is a common Indo-Pacific reef fish named for the black-and-white mask across its face. Unlike most reef fish, it is active mainly at night, resting during the day and coming out to feed after dark. It grows to about 20 cm.
Also known as: moon butterfly fish, raccoon butterfly, moon butterflyfish, racoon coralfish, redstriped butterflyfish, racoon, raccoon butterfly, red-striped butterfly-fish, spotted butterflyfish, moon butterfly fish, raccoon butterflyfish, racoon butterflyfish, raccoon butterflyfish, red-striped butterfly-fish
Two fixed marks settle it. First, the face: a black bar through the eye with a clear white block behind it, like a mask. Second, the small black spot on the narrow stalk just before the tail. Together with the slanting stripes running up the yellow-orange sides, these are easy to see from a normal viewing distance.
The body is oval and flat-sided, orange-yellow overall, darker along the back. A broad black bar covers the eye, with white behind it, so the face looks masked. Slanting reddish-brown stripes run up the flanks, and shorter yellow stripes sit just behind the head. There is a black spot on the narrow part of the body just in front of the tail.
It lives across the tropical Indo-Pacific, from East Africa to the islands of the central Pacific and north to southern Japan. It also turns up in the southeast Atlantic off South Africa. Look for it on seaward reefs and the shallow reef flats of lagoons. Young fish stay among the rocks of inner reef flats and in tide pools. It has been recorded as deep as 170 m, but divers usually meet it in shallow water.
In aquariums, this fish is often bought just to eat pest anemones such as Aiptasia, which it can clear from a tank within a few weeks.
Describe what you saw and we name it, then keep every species you find in your Oceandex.