The Butterflyfish family (Chaetodontidae) owes its scientific name to two Greek words, on the one hand chaeite meaning hair and on the other odontos meaning teeth. As we will see later, these words refer to their teeth. This family of fish, with diurnal habits in tropical marine waters, generally inhabits reefs at depths of less than 20 meters, although some species can be found up to 180 meters deep. The waters of the region between Australia and Taiwan are where there is the greatest diversity and abundance of Butterflyfish. In contrast, the Atlantic Ocean is home to only 14 species, while in the Pacific the number is reduced to 4 species.
The body of the Butterflyfish is markedly compressed in the lateral plane. They have a small and extensible mouth, which is located in a terminal position. Their small mouth has rows of teeth that look like a brush, a feature from which the name of this fish family has been derived. Its operculum has no spines. The coloration of the Butterflyfish is undoubtedly something that makes most species of this family of fishes extremely striking. The patterns are usually very intensely colored, with black, white, blue, red, orange and/or yellow. They usually have a black spot in the eye area, or a black band across the eye region. In addition, on the dorsal fin or the back of the body, many Butterflyfish species have another black spot, which is believed to confuse possible predators and do not know where the head and tail of the animal is. Generally, the different species of Butterflyfishesare between 12 and 22 cm in length, with certain species reaching 30 cm in length, such as Chaetodon lineolatus.
The dorsal fins of Butterflyfishes are unique and continuous, with certain species having a slight indentation of their dorsal fin. It is usually composed of 6-16 spines followed by 15-30 soft spokes. The anal fin has 3-5 spines, although mostly 3, followed by 14-23 soft spokes. The caudal fin has a margin between rounded and emarginated, but never forked. It has 15 branched spokes.
The diet of Butterflyfishes consists predominantly of invertebrates and coral polyps. There are species whose diet is based on zooplankton, these species being generally gregarious and forming large schools of fish. On the contrary, the rest of the species are animals with a marked territorial character, and therefore solitary or forming pairs. There are 129 known species of Butterflyfishes, organized in 12 different genera.