Butterflyfishes, members of the family Chaetodontidae, include more than 80 species and flourish in all the tropical seas, and even in some temperate waters. At least 12 species are found in the Red Sea: six of these species are endemic and are not found outside the Red Sea and its southern entrance. The remaining species are also found in other regions of the Indian Ocean.

Butterflyfishes range in size between 10-20 cms and prefer to live near healthy coral reefs in the 5-15 m depth range. In general, they have flattened deep bodies that give them exceptional manoeuvrability in confined areas. They also have a protruding snout with a tiny mouth that allows them to nibble at coral polyps. Most of the Red Sea species have some form of an eye mask to camouflage eye movement. Most species prefer to live in pairs, and sometimes in larger groups.

No reef fish is more closely asociated with the Red Sea than the unmistakable endemic lemon butterflyfish (Chaetodon semilarvatus) with its unique yellow body and greyish eye mask. Known locally as tabag (saucer), this beautiful and tame species is frequently seen hanging motionless near the reef, allowing divers to approach closely making it one of the most photographed fishes in the Red Sea.

In terms of behaviour, the Red Sea bannerfish (Heniochus intermedius) is the closest species to the lemon butterfly fish, although it tends to be more mobile. Known locally as abu sharaa (with sail), it is also endemic and is frequently misidentified as one or other similar-looking species that live in the Arabian Gulf and Indian Ocean. In certain locations of the Red Sea, the bannerfish and the lemon butterflyfish school together and remain there for long periods of time.

The orangetail butterflyfish (C. paucifasciatus), another colourful species, is usually seen feeding on table corals. It is a territorial fish and fights frequently erupt between members of the same species over feeding territories. An orange stripe runs vertically over the eyes of this species, and its creamy-white body has several chevron markings.

Several other species are classified as reef grazers, since they are always on the move to feed. These include the exquisite oval-shaped butterflyfish (C. austriacus), the giant butterflyfish (C. lineolatus) which is the largest species, and the orangeface butterflyfish (C. larvatus) which is probably the rarest. On the other hand, the threadfin butterflyfish (C. auriga) and the raccoon butterflyfish (C. fasciatus) are very common in the Red Sea. The latter is a very daring species that will follow divers persistently looking for a handout in frequently dived locations.

Most butterflyfish species are diurnal and spend the nights inactive between the corals. During sleep their bright colours tend to fade and spots develop. In addition, they erect their dorsal spines for protection.

The main diet of butterflyfishes includes coral polyps, algae and zooplankton. Some species also like to nibble at weak jellyfish by manoeuvring their bodies carefully to avoid the stinging tentacles. During a dive on a fringing reef south of Jeddah, I once observed more than 100 butterflyfishes uncharacteristically feeding together near the surface. It turned out that it was low tide and plankton-rich water from the lagoon was gushing from a crack in the reef. The butterflyfishes seized the opportunity and went into a feeding frenzy accompanied by schools of unicornfishes.

It is believed that butterflyfishes represent part of the diet of sharks and other large predators on the reef. I have also seen an electric ray trying to devour a butterflyfish, although it was not clear if the ray had deliberately stunned the fish. Unfortunately humans also exploit butterflyfishes. Ironically their sheer beauty is a major disadvantage since it means that they are highly prized by fish collectors. It is my belief that the introduction and enforcement of laws banning fish collecting will ensure that these beautiful creatures will continue to be a source of pleasure forever.