RED SEA Butterflyfishes

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.