A demon stingerfish, Lembeh Straight, Indonesia. (Credit: Bernard Dupont/Flickr)

The venomous demon stingerfish moves like a crab

  • July 03, 2015

This venomous fish looks like the ocean bottom, but it walks more like a crab

Contributor
Becky Crew

Becky Crew is a Sydney-based science communicator with a love for weird and wonderful animals. From strange behaviours and special adaptations to newly discovered species and the researchers who find them, her topics celebrate how alien yet relatable so many of the creatures that live amongst us can be.

THEY MIGHT LOOK like strange, stone gargoyles propped up on the seabed to ward off any evil spirits, but this frightful pair cares about as much about the fate of everybody's eternal souls as those dead eyes and frowny mouths would suggest. In fact, considering the demon stingerfish's name, a better bet would be that they'd welcome those evil spirits with open... fins?

Demon stingerfish (Inimicus didactylus) are found in the warm, shallow waters of Australia from down around the northwestern coast of Western Australia to up around the Northern Territory and Queensland. The nocturnal species spends its days partially buried in the muddy sand of seagrass beds and coral reefs, covering itself in extra debris to keep camouflaged.

Stonefish cousin a curious crab walker

Closely related to the highly venomous members of the stonefish genus (Synanceia), the demon stingerfish can pack a painful punch as well. The sharp ends of its dorsal fins are laced with a potent toxin that will inflict a nasty wound if you're unlucky enough to stomp on one with your bare feet. If you're lucky, the demon stingerfish will see you first and start flashing its bright red pectoral and caudal fins at you as a warning.

An even worse fate awaits those that the demon stingerfish is actually hunting. This ambush predator - also known as the bearded ghoul - will lie in wait and thrust those spines into any unsuspecting prey, the venom incapacitating it for easy digestion.

What makes this fish truly unique is its bizarre method of locomotion. Those weird little 'fingers' that look like crab's legs sprouting from either side of its face are strong and flexible enough to gently drag the fish along the sea floor, "like Thing from the Addams Family," as Esther Inglis-Arkell points out at io9.

You can see one moving about on its finger-tentacles in the video below: