Yellow Margin Triggerfish

Learn about the Yellow Margin Trigger Fish on Koh Tao

Yellow Margin Trigger Fish on Koh Tao can often be seen whilst scuba diving or snorkeling as they cruise around the reef or excavate coral.

Yellow Margin Trigger fish have a beautiful color and they glide around quickly and effortlessly in search of food and can be seen turning over rocks and pieces of coral out of curiosity.

Where to find the Yellow Margin Trigger Fish on Koh Tao

Yellow Margin Trigger Fish can be seen at many dive sites including Green Rock, Twins Pinnacles, Junkyard Reef, Aow Leuk and Laem Thian.

During the months of March – May they visit Green Rock in numbers as they settle down and set up their nest for breeding season.

How to identify the Yellow Margin Trigger Fish

Yellow Margin Triggerfish get their name from the yellow markings on the end of their fins and their body can be a range of colors made up of pink, yellow, turquoise, black and they have horizontal grooves around their eyes.

Their caudal (tail) fin is a similar color to their other fins with yellow markings on the edge, which end in a point at the top and bottom unlike the Titan Trigger Fish that has a flat shape.

Trigger Fin

A common behavioral trait with Trigger Fish is their ability to lock their front dorsal fin when they feel threatened and this is no different for the Yellow Margin Trigger fish.

This defensive behavior can be seen when they are in nesting season and protecting their young and like the Titan Triggerfish, they create a nest in the sand by blowing jets of water.

Yellow Margin Trigger Fish Characteristics & Behaviour

Yellow Margin Trigger Fish can grow up to 60cm in length and typically feed on marine life such as crabs, tunicates, sea urchins and other smaller fish.

They also feed on live coral and can be seen lifting and turning over large pieces of coral and for this they have extremely strong teeth and a small shaped mouth, which makes their jaw very strong.

Yellow Margin Trigger Fish can often be seen swimming upside down or backwards as their strong fins work together and they are extremely agile and can be seen showing off their buoyancy skills to scuba divers.

Interesting Facts about the Yellow Margin Trigger Fish

Yellow Margin Trigger Fish will find narrow crevices to take shelter whilst they sleep at night and they will lock their Trigger fin in place, which can make it more difficult for hungry predators to drag them out.

Yellow Margin Trigger Fish can independently rotate each of one their eyeballs, which makes them excellent at guarding their eggs.

Trigger fish are highly intellectual fish and have shown that they learn from past experience and they will often use nearby rocks or coral as tools to break open urchins or other tasty shell fish.

However, this method can leave a path of destruction around the reef and they are usually followed around by fishy friends who pick up any leftover scraps.