Typhlonectid amphibians

Often mistraded as a "rubber eel", the Rio Cauca caecilian (Typhlonectes natans) is actually an aquatic member, of a primarily fossorial, and non-aquatic clade of vertebrates, the Gymnophiona or caecilians. The confused appellation of "Sicilian worm" is attested, in North American aquarium retail, but these are neither worms nor eels. Rather, they are amphibians, though there is some debate, as to where Gymnophiona fits in the amphibian tree. The bulk of evidence would have Gymnophiona and their fossil relatives, the Albanerpetonidae, as sister to the salamanders, Urodela - forming a descent group, named Procera, that excludes the frogs, Anura.

Ublike their relatives that burrow, the typhlonectids are natural inhabitants of acidic to circum-neutral freshwaters, in the Neotrooical Realm. Ecologically, they are scavengers similar to marine hagfishes, swarming around carrion, and even sharing with them, through convergent evolution, a similar defensive slime coating. Typhlonectes natans also forages prey such as insects, shrimp, frog tadpoles, frogspawn, and small fish. This foraging habit leads to much detritus in their guts, and it is unknown wether Typhlonectes ingest detritus deliberately, or digest decaying plant material for its nutrients. Probably, it is ingested accidentally, in the course of foraging. T. natans grows to around 50 cm (20 in) long.

In the aquarium, T. natans like a high temperture, as befits their origins in northeastern South America. However tempertures over 30 degrees, can induce heat stress on these animals, so 26-31 degrees centigrade is a fair approximation, of their wild habitats. A pH between 6 and 7 would also reflect the locations, where T. natans has been collected in the wild. Sudden drops is in pH can be harmful to these amphibians, and the dH must be less than 5.6. Just about any defrosted, meaty food is eaten, but fast swimming fish sharing their aquarium, may outcompete the caecilians for it. It is best to feed them at night, because they are nocturnal, and forage primarily by oflaction. Quite unsurprisingly for such a generalised carnivore, T. natans also consumes singing pellets in the aquarium.

The aquarium layout should feature a soft substrate, deep enough for these animals to burrow in, and hiding places such as bogwood. The decor should be rough textured, but not sharp, because Typhlonectes rub on items in their environment, to shed their skins. T. natans is often found, amid aquatic vegetation, including floating plant life. In the aquarium, this species benefits from floating plants, because it will use them for shelter, and they diffuse the light from above. Though T. natans are gregarious by nature, the males can be nippy towards one another, and even to female tankmates. Small fish such as neon tetras, might not be safe from these opportunists come night time, so all tankmates of T. natans, must exceed the size of their heads, to be on the safe side. Interestingly, T. natans has been housed productively, with the Surinam toad, Pipa pipa.