Diving with Titan Triggerfish

Terrible 'Old Evil-eye'

You have probably seen them before and not doubt been warned of the dangers they pose when protecting their young but how much do you know about triggerfish? Find out more about this common reef inhabitant and understand why it has torn off a few ears over the years and caused so many bruises - is it just misunderstood? The titan triggerfish is a beautiful and robust reef creature just waiting to be discovered ...

Known scientifically as Balistoides Viridescens, these solitary creatures have been known to attack divers and inflict serious injury. Luckier divers return with holes in their fins (the fish seems attracted to colourful fins, which actually reduces the risk of personal injury) while more misfortunate divers have been knocked out cold or suffered from bite wounds requiring medical attention.

Regularly spotted at the Phuket diving islands such as Racha Yai and certainly one of the more antagonistic species of fish found in Thai waters, titan triggerfish are not known as a diver's best friend. However, despite looking quite mean with their beady, swivelling eyes, they're quite easy to deal with, with the right approach.

Why the aggressive behaviour, one might wonder? Hard to say. While some triggerfish are merely reacting to what they perceive as threats to their nesting grounds - definitely a lesson for divers to respect the habitat of these fish - others seem to do so for the fun of it. This much is clear - titan triggerfish are extremely territorial by nature. The male stands guard over its nest and will charge at any divers or fish that cross into its territory (the zone in a full circle directly above its nest.

Bites should be taken seriously as they are ciguatoxic. Ciguatoxin is a natural poison which is found on some tropical reefs. It infects fish which feed on marine algae. While harmless to the fish, even small amounts can have a harmful effect on humans. In cases of extreme poisoning, it may cause heart attacks, paralysis or death.

Triggerfish Fact Sheet

Family name: Balistidae
Order name: Tetraodontiformes
Common name: Titan Triggerfish
Scientific name: Balistoides viridescens

The balistoids are laterally compressed, generally rhomboid shaped fishes, although a few species such as the clown triggerfish, are slightly elongated. They have a non-protrusible upper jaw, with hard, specialised teeth that in most species are designed for cracking the shells of various hard-shelled invertebrates. They have independently rotating eyes, and their pelvic fins are fused into a single spine. They have two dorsal fins, the first of which is comprised of three spines, and this is where the trigger fish derives its name. They can use this spine, along with the ventral spine, to lock themselves into coral heads or rock crevices when threatened, and once they do they are immovable!

Its body is heavily scaled and is generally green to dark grey in colour, with yellow or green fins with black tips, and a lower jaw, dark grey or purple in colour. In Thailand, the fish are predominantly yellow in colour.

Titans are also known as the "Black-tipped" or "Moustached Triggerfish" due to their appearance - they have dark markings above the mouth which look like a moustache - and black edgings on their fins.

Its snout comprises about one third of its total length and its mouth is small with chisel-like teeth. Titan triggerfish can accelerate for short distances at a fairly surprising speeds. They can generally be found in the Indian Ocean and central Pacific at depths of around ten to thirty metres.

It is the largest member of its family. Most grow 40 - 60cm in length, although there have been reports of larger ones up to 75cm lurking around as well.

While they may enjoy taking a nibble out of divers, titan triggerfish tend to feed on hard corals, hard bodied benthic invertebrates and algae.

Dive Sites

More detailed information on titan triggerfish diving destinations:

Fiji

Indonesia

Thailand

Dive The World Recommendations: Racha Yai in Phuket and Phi Phi Islands.

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