Love Them or Hate Them Titan Triggerfish Are On Almost Every Phuket Diving Site
With a head that’s 2/3rds of it’s body mass, independently moving weird googly eyes and a set of teeth that wouldn’t look out of place on a hyena, the titan triggerfish is not going to win any modelling contracts but they can add a little excitement to a dive.
They’re a very prominent fish on Phuket’s reefs, signs of there activities are everywhere – deep excavations in the sand, broken corals, sea urchin spines scattered around and the odd digit or chunk of flesh from a diver are a sign of their presence and current disposition.
A Brief Bio
Titan triggerfish (Balistoides viridescens) are the largest of the triggerfish family in the indo-pacific and grow up to 75cm in length (it appears much larger when it’s attacking). They feed on molluscs, urchins, crabs, tube worms and other invertebrates, they also seem happy to feed on carrion if the opportunity arises.
The first spine of the dorsal fin can be locked into place and is from where the triggerfish family gets it’s name. At night the triggerfish wedge themselves into tight gaps in the coral and use the trigger to lock them in place making it very difficult for predators to get them out. The trigger is also used as a display to others of the same species and a warning to would be attackers.
Why Do Titan Triggerfish Attack Divers?
For fun would be my response but scientists believe that they’re protecting nest sites, and anything that wanders into the strike zone is fair game. The zone that needs to be avoided is an expanding cone directly above the nest so swimming upwards doesn’t help, you have to swim away along the bottom preferably keeping your fins towards the fish, a better option is to put your guide between you and the angry titan.
The nests are usually found in fairly shallow water in sheltered bays. Racha Noi and Racha Yai are definitely the preferred areas around Phuket, it’s very rare to hear of attacks on other dive sites even though titan triggerfish are present.
Although titan triggerfish supposedly attack only during nesting, that doesn’t seem to be the case in our area and they will sometimes defend a territory even if there isn’t a nest. Doesn’t seem to be so bad nowadays but there has been periods in the past where certain dive sites felt like you’re negotiating a minefield. We will be aware of the fish with attitude and try to steer you clear of them.
Most of the time the titan triggerfish will target the fin of the diver but there’s plenty of recorded attacks on other parts of the body that have left quite severe wounds requiring hospital treatment and in the worst cases some stitches and cosmetic surgery.
Why Not BBQ Them All?
It’s obviously morally wrong to remove a fish just because it’s a bit of a nuisance, it’s their territory not ours and they are a key member of the reef community. Titan triggerfish are often accompanied by sand perch and checkerboard wrasse who take advantage of the vigorous excavations to grab some food for themselves. They’ll also bite off pieces of acropora coral to reach hidden shellfish which actually helps the coral beds proliferate.
Titan triggerfish are one of the few fish that actively predate on healthy adult crown of thorn starfish and help keep their numbers in check. Enough reason not to slap them on the barbie but the fact that titan triggerfish can carry ciguatoxin should remove any lingering doubts.
Approach With Caution
We have sharks, venomous snakes and venomous fish that divers have a natural fear for and treat with caution but will happily approach the weird looking swimming rugby ball to get a photo. The best place to observe a titan triggerfish is from behind your guides shoulder. They’re usually absolutely fine but let your guide assess it’s state of mind and give the OK before approaching to observe or take a photo of this oddity with attitude.
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