Monacanthidae Bahamas | ROLLING HARBOUR ABACO

WTF? (WHAT’S THAT FISH) 5: THE FILEFISH

The jocularly-named WTF? series is designed to shed an underwater spotlight on some of the odder denizens of the coral reefs and surrounding waters. I don’t want to earn a reputation for being ‘lookist’, but frankly the appearance of some of these creatures – I give you BATFISH or FROGFISH or REMORAS as examples – is baffling. The filefish group is not as extreme as some in the downright weird category, but if you see one you might just find yourself muttering into your facemask “wtf?”

Scrawled Filefish ©Melinda Riger @ G B Scuba

Filefish (Monacanthidae) are found in tropical and subtropical oceans worldwide. They are related to triggerfish, trunkfish and pufferfish, and have regional names that include leatherjacket, foolfish, and shingle. There are more than 100 species of filefish, of which only a few are found in Bahamian waters. The species featured here are a mix of scrawled, white-spotted and orange-spotted filefish.

Filefish White-spotted ©Melinda Riger @G B Scuba

HOW DID THEY GET THE NAME?

In the image above, you can just see a flattened spine on top, above the eye and pointing backwards. This is the ‘retracted’ state. There is a small secondary spine that serves to prop up the main spine when it is in the upright position. This is it seems, the file – although the Greek-derived family name Monacanthidae literally means ‘one thorn’. So why isn’t it a thornfish, you may well ask. And I may well not respond.

This filefish’s ‘spine’ seems to have flopped over to one side White Spotted File fish

These fish have snouts with small mouths and specialized teeth with an inner and outer set on each jaw. They are to an extent shapeshifters, and can quickly make themselves appear larger for defensive purposes. In some individual species, there are marked differences in body shape and coloration.

An orange-spotted filefish with its spine erect, making for a cave – a place of safety Filefish, Orange Spotted ©Melinda Riger @ GB Scuba

The fins of a filefish are small, and they are rather sedate swimmers. Sometimes they simply like to drift with their heads pointed downwards, eyeing patches of seagrass or seaweed for prey. Some species are largely vegetarian. Others eat small invertebrates. Some even feed on corals. Their predators – especially the juveniles – include tuna and dolphins (mahi-mahi).

ADDITION Capt Rick Guest has helpfully expanded on juvenile filefish: “The juveniles hang under sea weed and flotsam eating small shrimps and crabs there. They, in turn become food for Mahi and other pelagic fish. The main thing with these guys is that the bigger they are, the more likely they are to be Ciguateric”.

At his suggestion I will write a post about the problem of the Ciguatera disease when I have had some time to do the research.

Scrawled File Fish

ARE THEY EDIBLE?

Good question. The answer, broadly is yes, though I don’t know if that applies to all species of filefish. They are certainly eaten in large quantities in the Far East. I don’t know about the Bahamas or the wider Caribbean. If anyone does, could you very kindly add a comment to this post. Recipes welcome!

Scrawled Filefish