Order : Anguilliformes
Family : OPHICHTHIDAE
Maximum Length : 300 cm

Snake eels, or worm eels, comprise the family Ophichthidae. As of 2024, Fishbase lists 62 genera and 347 species in this family (many genera only have one or two species, which suggests a great deal of evolutionary divergence). They reach a maximum length of around 3 metres, but most species are considerably shorter.

They reach their greatest diversity in tropical waters, where they have adapted to a variety of habitats including shallow coral reefs, coastal mudflats, mangrove and rivers.

Most species are benthic, seeking out their prey on muddy or sandy substrates : these eels may spend much of their time hidden from view within such sediments. Crustaceans, including crabs and prawns, form the bulk of their diet which also includes fish.

Their fins are much reduced, or completely absent; this allows them to burrow into soft substrates without hindrance. Both the snout and tails may be sharp and bony, allowing some species to burrow backwards as well as forwards. Their skin lacks scales, and is very smooth.

Some species have attractive patterns of blotches, spots or bands on a brightly coloured background, while others are plain brown.

Fig 1 : A species of Pisodonophis from mangrove habitat in Singapore, tentatively the Longfin Snake-eel Pisodonophis cancrivorus.

Fig 2 : The same specimen searches the entrance to a burrow, possibly in search of crabs. The rounded, pectoral fins are being held perpendicular to the body, perhaps to stabilise the body as it searches.


References and links :

Fishbase - Ophichthidae