Have you ever seen a fish that you had no idea existed?  Many people have been experiencing that on Sanibel and Captiva's beaches lately.  Recently, some interesting fish have washed up on our shores, including peculiar batfish species.

Two batfish found on the beach near Sundial Resort on Sanibel. 

Two batfish found on the beach near Sundial Resort on Sanibel. 

Batfish are subtropical fish that have a wide, relatively flat body covered in little bumps with pectoral fins that look like limbs. Their flattened shape allows them to successfully live a demersal lifestyle; meaning they live close to or on the seafloor. They can often be observed by snorkelers slowly moving around the bottom or flattened down into the sand to hide from predators.

The batfish has a unique way of acquiring its food. It has a modified rostrum, or nose, that is coupled with a spine. This modified structure on its face can be used to detect and lure in slow moving prey on the seafloor. Once the desired food is in range, the batfish swallows it whole in one large gulp. They typically eat crustaceans, shelled mollusks, bristly polychaete worms, and even the occasional fish.  

The head of a large, live polka-dot batfish. Photo source. 

The head of a large, live polka-dot batfish. Photo source

In Southwest Florida, there are a few species of batfish one might see.  Some of the local batfish species include the longnose batfish (Ogcocephalus corniger), the polka-dot batfish (Ogcocephalus cubifrons), and the spotted batfish (Ogcocephalus pantostictus). The longnose batfish has a long protrusion from its rostrum, which differentiates it from other species. The polka-dot and spotted batfish can often look similar, but the differences in body shape and mouth width can help one distinguish between the two species. 

Although these unusual creatures may look threatening, there is nothing to be alarmed about.  They cause no harm to humans and live peacefully on the seafloor. The IUCN Red List has listed many species of batfish as species of least concern, which means they have widespread populations and very few threats. So the next time you see one of these interesting vertebrates, you can tell everyone that batfish are docile creatures that slowly roam the seafloor on their limb-like pectoral fins.