Scuba Diving with Triggerfish in Koh Tao

Scuba Diving with Triggerfish in Koh Tao

Triggerfish often have a rough reputation among divers, but not all species fit that mold. On Koh Tao, you'll encounter two main types: the calm Yellowmargin and the more assertive Titan. While the yellowmargin triggerfish isn't territorial, it can still be aggressive at times, but it's the infamous titan that divers need to watch out for! In the Gulf of Thailand, many divers have wild and funny stories about Titan Triggerfish; during mating season, they become fiercely territorial, defending their nests against intruders.


Triggerfish in Koh Tao

What to Watch Out For?

The titan triggerfish, though fascinating and beautiful, has a notorious reputation among divers. For most of the year, they're pretty chill, but during nesting season, they can get nasty. And by nasty, I mean really nasty! While they can't cause serious or life-threatening injuries, their large, sharp teeth are designed to crunch corals, and they pack a powerful bite that’s best avoided.

So, why do they get so aggressive? Titan triggerfish are extremely territorial, especially during nesting season. Not only do they not tolerate other fish in their territory, but they also object to humans entering it. Usually the fish simply tries to escort the intruder out of its home, or adopts a defensive posture. Most of them are just protecting their nests, but some seem to enjoy snapping at divers' fins just for fun. Luckily, there are clear signs to watch for indicating that trouble might be on its way!

1. The "Trigger"
The titan triggerfish earns its name from its distinctive dorsal fin. Made up of three spines, when threatened, triggerfish can raise the first two spines, creating a sharp defense mechanism. The long first spine is held in place by the shorter second spine and can only be released by depressing the second 'trigger' spine, hence the name triggerfish. The 'titan' part of its name refers to its size, as it's the largest triggerfish in its habitat.


Koh Tao Titan Triggerfish

If you see the spine raised, it's a clear sign that the triggerfish is feeling threatened or anxious. This serves as a warning for divers to swim the other way to avoid any potential aggression.

2. The “Evil Eye”
When you catch the "evil eye" from their independently rotating eyeballs, it's time to steer clear! If their eyes are twitching or you see them rolling onto their side while glaring at you, it's a clear signal to retreat before they make a move. Keep an eye out for their raised black trigger fin, a sure sign of an impending attack!

How to Get Outta There

If you’ve unknowingly bumped into a titan triggerfish intent on munching on your dive gear, don’t panic! There's a way out!

Triggerfish in Koh Tao

First, stick your fins between you and the troublemaker to create a barrier. Most times, the triggerfish is just trying to push you away. But if it decides to take a nibble, better your fins than your body, right?

The Getaway Plan

Their territory forms an upside-down cone around their hidden eggs, so swimming upward won't get you out of the nesting zone – we've witnessed triggerfish chasing divers all the way to the surface. The key? Go horizontal! Keep an eye on them as you swiftly make your lateral escape.
Once you're out of their zone, they'll cease their pursuit. They'll return to their nest, and you'll head back with some adrenaline-packed tales to regale your buddies!

Misunderstood Titans?

While the titan triggerfish's bad repuation isn't entirely unfounded, it's worth noting they're (mostly…) safeguarding their territory and offspring from what they perceive as intruders.
Divers who've crossed paths with nesting triggerfish might understandably feel jittery encountering them underwater and may instinctively steer clear. This caution is warranted during nesting season, but not so much the rest of the year!

Triggerfish hand signal

Your dive guide typically gives you a heads-up if you're diving where nesting triggerfish hang out. They're experts at spotting potential trouble spots and steering clear. Just follow their lead, and you will be fine! And if you do happen upon a triggerfish looking a bit aggressive, you now know the warning signs and how to make a quick exit safely!

Despite their notorious reputation, triggerfish are actually fascinating and beautiful creatures, known for being smart and playful. Yeah, they can be a bit mischievous at times! But hey, we love them! Whether you're a total beguinner or an experienced diver, encountering a triggerfish in Koh Tao is gonna be a highlight of your dive for sure!

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