Finescale Triggerfish: Armored, Clever, and Strong-Jawed

The finescale triggerfish is a stout, powerful reef fish with tough skin, strong jaws, and a clever locking spine that wedges it into crevices. It's one of the larger, more confident fish you'll meet on the reef. Here's how to spot one snorkeling near Jacó, plus five fun facts.

Finescale Triggerfish · Balistes polylepis

How to spot the finescale triggerfish near Jacó

Look over rocky reef and rubble for a deep-bodied, blue-gray fish moving with a rowing motion of its top and bottom fins. The finescale triggerfish swims in an unmistakable up-and-down ripple rather than beating its tail. It's often out in the open, unafraid, nosing around the bottom for food.

5 fun facts about the finescale triggerfish

• A built-in lock. It can raise a stout first spine on its back and lock it in place with a smaller 'trigger' spine — wedging itself into a crevice so tightly that predators can't pull it out.
• Jaws like pliers. Strong teeth and jaws let it crunch hard-shelled prey like crabs, urchins, and mollusks that most fish can't touch.
• It rows, not wags. Instead of beating its tail, it sculls along with its top and bottom fins — a smooth, rippling motion that's easy to recognize.
• A sand-blower. It blows jets of water at the sand to uncover buried prey, and will even flip sea urchins to get at their softer underside.
• A fierce nest guard. When breeding, triggerfish fiercely defend their nests on the bottom and will chase off anything that drifts too close.

The finescale triggerfish is just one of many characters down there. See the whole cast in our Snorkel Jaco fish directory, or read real guest photos and reviews on the Snorkel Jaco reviews.