The clown triggerfish (Balistoides conspicillum), also known as the bigspotted triggerfish, is a demersal marine fish.

Taxonomy

Although it is in the genus Balistoides alongside the titan triggerfish (Balistoides viridescens), the genus is not monophyletic and requires revision. As a result, the clown and titan triggerfish are not each other's closest relatives. The clown triggerfish is possibly most closely related to species of the genus Melichthys and the orange-lined triggerfish (Balistapus undulatus).

Description

left|thumb|Juvenile, in South Africa

thumb|In the [[Maldives]]

The clown triggerfish is a fish which grows up to 50 cm (19.7 inches) in the wild, however, in captivity it does not usually reach that length. Its body has a stocky appearance, oval shape and compressed laterally. The head is large and represents approximately one third of the body length. The mouth is small, terminal and has strong teeth.

The first dorsal fin is composed of three spines, one of which is longer and stronger. It is erectile and hidden in a dorsal furrow. This set of dorsal spines composed a trigger system which is a characteristic from the family Balistidae. The second dorsal fin is similar in shape and size to the anal fin which is symmetrically opposed to it. The pelvic fin is reduced to a ventral protrusion.

The background coloration is black. Half of inferior part of the body is marked with big white spots which are more or less round. The area around the first dorsal fin is crossed by yellowish sinuosities which draw like a network reminding the leopard's patterns. There is a yellowish ring around the mouth, which is surrounded by another fin white ring. A white stripe ride the snout just under the eyes level. The second dorsal fin and the anal fin are white and underlined with a yellow line at their base. The caudal peduncle has a yellowish blotch on its top part and has three horizontal sets of spiny scales. The caudal fin is yellowish in its center and has black margin. Juveniles have a black background coloration spangled with small white spots, the extremity of the snout and the base of the first dorsal fin is yellowish.

These scales are thick, weakly overlapping, with a rhomboid shape. Each scale has two layers: the topmost layer being bone and the lower layer being collagenous.

This fish has teeth that continuously grow. These teeth help them when feeding on crustaceans.

Distribution and habitat

thumb|In Indonesia

The clown triggerfish is widely distributed throughout the tropical and subtropical waters of the Indian Ocean and in the western Pacific Ocean.

Biology

thumb|With fully extended dorsal and pelvic spines, in [[New Caledonia]]

Although the clown triggerfish is widely distributed, it occurs in low numbers in the wild. However, this fish can be locally abundant in areas with high biodiversity. They have also been recorded feeding on crinoids.

Behaviour

This triggerfish has a diurnal activity, is solitary and defends a territory. It can be hard to find this fish in its habitat. It can be very aggressive with other fish and congeners.The clown triggerfish can be sociable the younger it is, however as it gets older, the less sociable and more aggressive it becomes.

The juvenile clown triggerfish are sought out after more than adults since juveniles are less aggressive towards other fish. They have been known to take out chunks of flesh while being hand-fed.

References

  • ITIS - Report: Balistoides conspicillum, Retrieved [mai, 30, 2013], from the Integrated Taxonomic Information System on-line database, Integrated Taxonomic Information System.
  • Bailly, N. (2013). Balistoides conspicillum (Bloch & Schneider, 1801). In: Froese, R. and D. Pauly. Editors. (2013) FishBase. Accessed through: World Register of Marine Species at WoRMS - World Register of Marine Species - Balistoides conspicillum (Bloch & Schneider, 1801) on 2013-05-30