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Blacksaddle filefish mimics a toxic toby
Blacksaddle fishfish is a cute, tropical fish found occasionally throughout Gorontalo’s coral reefs. However, its saddle patterning closely resembles a toxic pufferfish.
A natural phenomenon where a harmless species mimics a harmful one is Batesian Mimicry. It gets its name from Henry Bates. He was a nineteen century English naturalist. He first detected this phenomenon among species of butterflies from the Amazon.
In Batesian mimicry, a mimic species will resemble a model species. In doing so, the mimic gains protection. So, predators mistake the harmless species for the harmful one.
Blacksaddle filefish and Blacksaddle toby
The scientific name of this filefish is Paraluteres prionurus. The toxic toby it resembles is Canthigaster valentine. Its skin and certain internal parts are toxic if swallowed. Tobies are small pufferfish species.
At a casual glance, both species appear identical! However, divers can carefully observe distinctions. Most noticeable are the differing dorsal fins. The dorsal fin of a Blacksaddle filefish will be long, extending all the way to the tail base. However, the Blacksaddle toby has a tiny dorsal fin near the tail.
Naturally, filefish have a dorsal spine located behind the eyes that tobies lack. Sometimes, a filefish will flick its spine upwards. More often, the spine tucks unseen onto the fish’s head. Only male Blacksaddle tobies have beautiful blue lines streaming behind their eyes. However, a male Blacksaddle filefish has four yellowish spines projecting from his tail base. These resemble a small brush.
Where to find Paraluteres prionurus
The Blacksaddle filefish live near the surface to a depth of 25 meters. Its maximum length is 11 centimeters. However, most are about half that size or smaller. This fish is scattered throughout Indo-Pacific waters. It prefers clear lagoons and coral reefs that face the ocean. Although adults are usually in pairs, they often swim with Blacksaddle tobies. This behavior gives extra protection to the mimic filefish.
For your chance to see a Blacksaddle filefish or toby, please make your dive reservations directly with Miguel’s Diving.