The Serpent Eel has an extremely elongate, rounded body, only 5 cemtimetres in diameter and is one of the longest eel species reaching a maximum size of 2.5 metres total length. The snout is long and conical with a single row of sharp teeth on each jaw and a larger row on the roof of the mouth, with the eyes relatively small. This species has pectoral fins, but lacks scales, pelvic fins and a caudal fin. The dorsal and anal fins stop just short of the tip of the tail leaving a hard rigid tip at the end which aids them in burrowing. They range in colour from sandy brown to olive green above and silvery below, with an arrangement of black pores on the head. This shape and colouring makes them perfectly adapted for burrowing in and becoming camouflaged amongst the sandy and silty bottoms in which they live. Adult serpent eels live in offshore sediments to depths of 300 metres, where juveniles are found in coastal waters and estuaries. They are a nocturnal species, living a cryptic lifestyle within a burrow, emerging so much as to expose only the eyes and part of its head, retreating entirely if threatened. The Serpent Eel feeds at night by ambushing any fish which dares to pass by.
Serpent Eels are found widespread overseas, however in Australia they are known to exist from the Noosa River, Queensland to Lancelin, Western Australia.
Other common names include Sand Snake-eel.
Occurrence at the Busselton Jetty
Rarely spotted from the Underwater Observatory due to their nocturnal, cryptic nature of burrowing, specimens have, however, been seen near the Busselton Jetty during night dives.