Opentopia Directory Encyclopedia Tools

Triggerfish

Encyclopedia : T : TR : TRI : Triggerfish


Triggerfishes are the brightly coloured fishes of the family Balistidae.

Marked by lines and spots, they inhabit warm coastal waters of the Atlantic, Mediterranean and the Indo-Pacific.

Their size varies from 30 cm (1 foot) to 75 cm (2.5 feet). 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.

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. Their small eyes, situated on top of their big 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.

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

Behavior

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. The Picasso triggerfish is relatively small, but due to its large size and powerful teeth the Titan triggerfish poses a serious threat to inattentative divers.

Picasso triggerfish (Rhinecanthus aculeatus)
Enlarge
Picasso triggerfish (Rhinecanthus aculeatus)

Redtoothed Triggerfish (Odonus niger) feeding on plankton
Enlarge
Redtoothed Triggerfish (Odonus niger) feeding on plankton

Titan triggerfish (Balistoides viridescens) with Orange-lined triggerfish (Balistapus undulatus) and Moorish Idols at the reef of Fihalhohi, Maldives
Enlarge
Titan triggerfish (Balistoides viridescens) with Orange-lined triggerfish (Balistapus undulatus) and Moorish Idols at the reef of Fihalhohi, Maldives

Orange-lined triggerfish (Balistapus undulatus)
Enlarge
Orange-lined triggerfish (Balistapus undulatus)

Black triggerfish (Melichthys niger) and its reflection
Enlarge
Black triggerfish (Melichthys niger) and its reflection

Genera

References

Wikimedia Commons has media related to:
[media]

 


From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.

Search Titles
0123456789
ABCDEFGHIJ
KLMNOPQRST
UVWXYZ?

E-mail this article to:

Personal Message: