Black eeltail catfish (Plotosus canius)

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Phylum Chordata > Subphylum Vertebrate > fishes > Family Plotosidae

Black eeltail catfish
Plotosus canius
Family Plotosidae
updated Oct 2019

if you learn only 3 things about it ...

It is small and usually hidden among seaweeds or under rubbish. Watch your step!

The 'whiskers' don't sting. They are used to find food in murky waters.

It has venomous spines. Don't touch it!

Where seen? These wriggly place eel-like fishes are sometimes seen on some of our shore. Usually seen alone, hiding in pools under stones or other debris on the shore, near seagrasses. Elsewhere, adults found mostly in estuaries and lagoons, and sometimes up rivers in nearly fresh waters.

Features: Adults can reach 90cm-1.5m long, those seen at low tide on our shores usually much smaller, about 4-5cm long. Body long, cylindrical and flattening into an eel-like tail. i.e., the dorsal and anal fins are continuous with the tail fin. Snout blunt with four pairs of 'whiskers' (called barbels) all around the mouth. One pair on the snout in front of the eyes, one pair on each side of the mouth and two pairs below the mouth. It lack scales and has a smooth slimy skin. It makes up for this 'nakedness' with venomous spines on the dorsal fin and on each of the pectoral fins. These tough spines can be locked upright, thus making an eeltail catfish unpleasant for bigger fish to swallow. Plain dusky-brown to black with a black dorsal fin tip and a pale belly. Tiny ones resemble black tadpoles.

Sometimes confused with Striped eeltail catfishes. The adults of these two eeltail catfishes may appear similar as the stripes on the Striped eeltail catfish fades with age. In Black eeltail catfish adults, the long barbels at the top of the snout can extend past the eyes. These barbels don't extend past the eyes in adult Striped eeltail catfishes. So far, those tiny juveniles seen schooling in dense balls on our shores turn out to be Striped eeltail catfishes.

Sometimes mistaken for sea snakes or eels (Family Muraenidae). Here's more on how to tell apart sea snakes, eels and eel-like animals.

'Whiskers' (barbels) at the top of the snout
can extend past the eyes.

Changi, Aug 05

Body may not be black, but tip of dorsal fin always black.
Changi, Apr 08

Don't touch! It has venomous spines on the dorsal fin and on each of the pectoral fins, which can be locked upright. The stings can be excruciating and long-lasting. Like other wild animals, the fish will sting only if provoked. So don't touch it, don't put your hand into holes or crevices.

What does it eat? It eats crustaceans, molluscs and fishes. It is adapted for hunting on the sea bottom in murky waters.The 'whiskers' (barbels) around the mouth do not sting, they help find prey where visibility is poor. The barbels have taste buds to help sense food. The fish also has a keen sense of hearing. Also a strong sense of smell, using their 'noses' (nostril-like openings on the snout).

Human uses: The large adults are harvested commercially for eating.

Black eeltail catfishes on Singapore shores

On wildsingapore flickr