By Bill Rhodes | Conservancy of Southwest Florida volunteer
When visitors to the Conservancy of Southwest Florida’s Dalton Discovery Center stop in front of the large patch reef tank, docents are happy to name its inhabitants and explain the formation of the patch reefs themselves, common in our Gulf waters. Among the fishes they describe is the burrfish — a small, odd-looking boxlike fish, strikingly colored with a brown, yellow and white pattern, covered in short, sharp spikes and sporting a parrot-like beak.
The burrfish (Chilomycterus spp.) is in the family Diodontidae, which is a branch of the puffer fish tribe. The Diodontidae’s hallmark trait are the spines adorning most of their bodies. Like all puffer fish, they have a unique method of protecting themselves from being eaten by larger fishes. When startled or under attack, the burrfish will rapidly draw water or air into its body and balloon out to at least three times its normal size. The sudden change in size hopefully scares off or deters their attackers. This tactic helps the burrfish elude becoming a meal in three ways — its sudden ballooning will startle an unsuspecting predator, which then sees a fish larger than themselves, or one simply now too big to swallow.
Found in the upper 30 feet or so of our coastal waters, the burrfish is predominantly found in seagrass beds, where it puts its hard, sharp mouth to good use, crushing and eating crustaceans, barnacles and hermit crabs. It is an omnivore; while happy to eat the other small fishes, mollusks and invertebrates it might come across, it will also graze on algae.
Observing it in the tank, it seems that the burrfish is a bit of a “lazy “swimmer, simply moving its fins to stay suspended. It may seem to be a weak swimmer, but that is because it’s mode of locomotion is unlike most fishes. It uses jet propulsion to move about — that is, burrfish move forward by squirting water out of their gills, propelling them forward.
Burrfish can be found in the western Atlantic Ocean as far north as Canada and south through the Gulf of Mexico. While not under major threat from either sport or commercial fishing, they are popular for aquarists, and caught for the pet trade. There appears to have been a decline in their numbers in the wild, which is likely due to the destruction of their coastal habitats and seagrass beds.
With their ability to balloon in size, their striking coloration and their sharp spines, they have been frequently caught by people who blow them up, dry and shellac them, turning them into ‘mementos’ for tourists — certainly not a fitting end to such an interesting and unusual fish.