Spotted Boxfish: A Fish That Swims Like a Box

The spotted boxfish is exactly what it sounds like — a small fish encased in a rigid, box-shaped shell of fused plates, puttering around the reef with whirring little fins. Males are a gorgeous blue and gold. Here's how to spot one snorkeling near Jacó, plus five fun facts.

Spotted Boxfish · Ostracion meleagris

How to spot the spotted boxfish near Jacó

Look low around coral and rocky nooks for a small, boxy fish that seems to hover and hum along on tiny fluttering fins rather than swim. Males are dark blue with golden spots; females and young are blackish with white dots. Its stiff, square shape is like nothing else on the reef.

5 fun facts about the spotted boxfish

• A body like a box. Its skeleton is fused into a rigid, armored box of bony plates, so only its fins, mouth, and tail can actually move.
• It hovers like a helicopter. Because its body can't flex, it steers with rapidly whirring fins, hovering and pivoting with surprising precision.
• Boys and girls look different. Males are striking blue-and-gold, while females and juveniles are dark with white spots — so different they were once thought to be separate fish.
• A chemical defense. When very stressed it can release a toxin into the water to deter predators — another reason it cruises along unbothered.
• Small and unhurried. Only a few inches long, it pokes slowly around the reef nibbling algae, sponges, and tiny invertebrates.

The spotted boxfish 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.