Matt Clarke on one of the weirdest fish to hit the shops for years, the blind, mud burrowing Bearded worm goby, Taenioides cirratus.
Common name: Bearded worm goby, Blood red dragon goby
Scientific name: Taenioides cirratus
Origin: Widespread, but rarely seen. Has been recorded from India, China, Japan, Indonesia, Sri Lanka, Thailand, Vietnam, Papua New Guinea and the Philippines.
Size: About 30cm/12". These ones were 10cm/4" long.
Diet: Gut analyses show that this species eats bottom-dwelling crustaceans and fish. They should take bloodworm and other frozen foods readily.
Water: These are estuarine fishes, so a little salt is advisable.
Aquarium: Setting up a biotope tank for these fellas might prove challenging. They are mud burrowers! Itani and Uchino (2003) poured resin into the burrows formed by this species, in both aquaria and the wild, to investigate burrow structure. They found that the fish produced a crateriform mound with several openings to a series of interconnected tunnels inside and numerous short "cul-de-sac" branches. They say that the goby actively processes sediment. The fish we photographed were happily living in a soft, silver sand substrate and appeared to be doing OK.
Similar species: These were originally in the subfamily Taenioninae, but have since been moved to the Gobiidae subfamily Amblyopinae. Gobies in this group are found in estuarine muds from Saudi Arabia, down the African coast to China, Japan and Australia. The genus is in need of revision and is thought to contain about 18 species including: alleni; anguillaris; buchanani; hermannii; coecula; gracilis; rugosus; jacksoni; eruptionis; cirratus; brachygaster; mordax; purperascens; snyderi; caniscapulus; limicola; nigrimarginatus and esquivel. As you'd expect, they are very hard to identify accurately.
Identification: The dorsal of cirratus should have 6 spines and 43-49 rays, and the anal should have a single spine and 42-47 branched rays, not that you'd be able to count them, though...
Notes: This is, without doubt, the oddest fish I have seen on sale for years. The fish has tiny rudimentary eyes, teeth on the outside of its lips and has evolved to live in soft estuarine mud burrows. It lacks colour (you don't need to be colourful if you live underground) and it can survive out of water for long periods if kept moist, which is presumably an adaptation for survival when the tide goes out. It can breathe air, too.
Availability: Since they spend most of their time burrowed into mud, these evade capture, so they've not been imported into the UK before. Tom Halvorsen Ltd imported these from India.
Price: About 10 each.