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What is a sarcastic fringehead? © Alamy

Sarcastic fringehead: The fish that fights with a kiss

Published: 07th December, 2021 at 11:00
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No, not something you call your mate when they've been scathing about your outfit, but a big-mouthed, purple-tongued, lip-wrestling, territorial fish.

It has an awesome name, with an attitude to match. The sarcastic fringehead is a big-mouthed, bolshy blenny that lives in the temperate coastal waters of California and Mexico’s Baja California.


These strange fish hang out in their ocean floor dens, which can be burrows, empty shells or even discarded plastic bottles. Males reverse in, bottom first, then defend their territories from other sarcastic fringeheads by dropping caustic one-liners. Only joking! Riled individuals actually face-off by slamming their huge, open mouths together.

Laterally-splayed jawbones and sail-like cheek membranes reveal a purple tongue, a double row of teeth, and a fluorescent yellow mouth rim. They look part fish, part Demogorgon from Stranger Things.

It’s basically a ‘who’s got the biggest mouth’ competition, where the victor bags the best den and a chance to mate. After the female lays thousands of eggs in the prized location and the male has fertilised them, he then defends his offspring with yet more oral aggro.

The name ‘fringehead’ refers to the floppy fronds of tissue that fall over the fish’s eyes, while the term ‘sarcastic’ is thought either to describe the animal’s sardonic closed-mouth expression, or to derive from the Greek word sarkázein, which means ‘to tear flesh’. Either way, the only thing that’s cutting about this fish is its set of teeth.

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Helen Pilcher
Helen PilcherScience writer, presenter and performer.

Helen Pilcher is a tea-drinking, biscuit-nibbling science and comedy writer, with a PhD in cell biology.


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