triggerfish n : any of numerous compressed deep-bodied tropical fishes with sandpapery skin and erectile spines in the first dorsal fin [also: triggerfishes (pl)]

English

Noun

triggerfish (plural triggerfish of triggerfishes)

1. any of several brightly coloured fish, of the family Balistidae, that inhabit tropical reefs, and have an erectile spine on its dorsal fin

See also

• humuhumunukunukuapuaa

Triggerfishes are brightly colored fish of the family Balistidae. Often marked by lines and spots, they inhabit warm coastal waters of the Atlantic, Mediterranean and the Indo-Pacific.

Anatomy and appearance

Their size varies from 30 to 75 cm (1 to 2½ ft).

Triggerfish have a roundish, laterally flat body with an anterior dorsal fin. They can erect the first two dorsal spines: the first one locks and the second one unlocks. This prevents predators from swallowing them or pulling them out of their holes. This locking and unlocking behaviour is why they are named 'triggerfish'.

They have a small pectoral fin, fused to one spine. Unlike the spine of a filefish, the spine of the triggerfish can be held in place by a second spine to make the fish more threatening to the predator. Their small eyes, situated on top of their large head, can be rotated independently. They have tough skin, covered with rough rhomboid-shaped scales that form a tough armour on their body. A big, angular-shaped head extends into a snout with strong jaws and sharp teeth, made for crushing shells. Each jaw contains a row of eight teeth, while the upper jaw contains another set of six plate-like teeth.

Behavior

Most are solitary and diurnal. They feed on hard-shelled invertebrates, a few feed on large zooplankton or algae. They lay their demersal eggs in a small hole, dug in the ground. Some species guard their eggs.

A few of the triggerfish species can be quite aggressive during reproduction season. In particular Picasso triggerfish and titan triggerfish viciously defend their circular nests against any intruders, including scuba divers and snorkelers. Their territory extends in a cone shape from the nest to the surface, so swimming upwards puts one further into the fishes' territory. A horizontal swim away from the nest site is the most sensible course of action when confronted by an angry triggerfish. In contrast to the relatively small Picasso triggerfish, the titan triggerfish poses a serious threat to inattentative divers due to its large size and powerful teeth.

Some species of triggerfish are known to make a sound akin to a grunt or snarl when taken out of the water.

Gallery

Genera

• Abalistes Bloch & Schneider, 1801
  • Abalistes stellaris : Starry triggerfish
• Balistapus Tilesius, 1820
  • Balistapus undulatus : Orange-lined triggerfish
• Balistes Linnaeus, 1758
  • Balistes capriscus: Grey triggerfish
  • Balistes ellioti
  • Balistes polylepis : finescale triggerfish
  • Balistes punctatus : Bluespotted triggerfish
  • Balistes rotundatus
  • Balistes vetula : Queen triggerfish
  • Balistes willughbeii
• Balistoides Fraser-Brunner, 1935
  • Balistoides conspicillum : Clown triggerfish
  • Balistoides viridescens : Titan triggerfish or mustache triggerfish
• Canthidermis Swainson, 1839
  • Canthidermis maculata: Spotted oceanic triggerfish
  • Canthidermis macrolepis : Large-scale triggerfish
  • Canthidermis sufflamen : Ocean triggerfish
• Melichthys Swainson, 1839
  • Melichthys indicus : Indian triggerfish
  • Melichthys niger : Black triggerfish
  • Melichthys vidua : Pinktail triggerfish
• Odonus Gistel, 1848
  • Odonus niger : Redtoothed triggerfish
• Pseudobalistes Bleeker, 1865
  • Pseudobalistes flavomarginatus Yellowmargin triggerfish
  • Pseudobalistes fuscus : Blue or rippled triggerfish, blue-and-gold triggerfish or yellowspotted triggerfish
  • Pseudobalistes naufragium : Stone triggerfish
• Rhinecanthus Swainson, 1839
  • Rhinecanthus abyssus
  • Rhinecanthus aculeatus Picasso triggerfish, lagoon triggerfish (USA)
  • Rhinecanthus assasi : Arabian Picasso triggerfish
  • Rhinecanthus cinereus
  • Rhinecanthus lunula : Halfmoon picassofish
  • Rhinecanthus rectangulus: Reef triggerfish or humuhumu-nukunuku-a-pua'a (Hawaii)
  • Rhinecanthus verrucosus : Blackbelly triggerfish
• Sufflamen Jordan, 1916
  • Sufflamen albicaudatum : Bluethroat triggerfish
  • Sufflamen bursa : Boomerang triggerfish
  • Sufflamen chrysopterum : Halfmoon triggerfish
  • Sufflamen fraenatum : Masked triggerfish
  • Sufflamen verres : Orangeside triggerfish
• Xanthichthys Kaup in Richardson, 1856
  • Xanthichthys auromarginatus : Gilded triggerfish
  • Xanthichthys caeruleolineatus : Bluelined triggerfish
  • Xanthichthys lineopunctatus : Striped triggerfish
  • Xanthichthys mento : Redtail triggerfish
  • Xanthichthys ringens : Sargassum triggerfish
• Xenobalistes Matsuura, 1981
  • Xenobalistes punctatus : Outrigger triggerfish
  • Xenobalistes tumidipectoris

References