August 28, 2006
Typhlonectes natans. The Caecilian Worm
The caecilian worm, Typhlonectes natans, is a member of the Order Apoda, a highly specialized group of tropical burrowing amphibians. Members of this order are characterized by the abscence of legs and tails. Despite being burrowers, these “worms” are some of the most readily available amphibians. They are sold in almost every pet store that carries fish. You may have seen them in a tank listed as “rubber eels” or “rubber worms”–“Sicilian worms” is another common name.
Caecilian worms range in length from five to fourteen inches and from 1/4 to one inch in diameter. The body of these amphibians ends in a cloaca, not a tail as in sirens and salamanders. Careful observation shows that they have rather large mouths and small eyes covered by skin, making them nearly sightless. Keep this in mind. If an animal is virtually blind it usually makes up for it with one of its other senses.
Keeping these amphibians in captivity can be more of a challenge than most people realize. First, let’s consider their habitat. Being burrowers that like mud, they are unsuitable as display animals. Probably the best setup for the animals’ well being is a 50/50 aqua-terrarium. An undergravel filter provides water filtration and circulation. Burrowing material is also beneficial; this could be moss or crumpled paper towels over gravel on the land area and just gravel in the water. I wouldn’t recommend mud, as bacteria goes wild in mud in a closed system, producing some truly horrendous odors.
The fact that the worms are burrowers and semi-aquatic gives some indication as to the kinds of food they prefer. Bottom dwelling aquatic organisms like crustaceans (fozen brine shrimp and dried krill work well) and insect larvae. Earthworms and redworms are also accepted. Don’t rule out pellet fish food either. In fact, try anything of size that will fit in their mouths. Since the worms can’t see the food they apparently find it by smell or even touch, so it’s a good idea to use foods that will hold up for a while in the water without dissolving.
Caecilians of this species have rarely, if ever, been bred in captivity, although gravid females have been imported and have given birth as captives. The female gives birth to several fully developed young four to five inches long. I was fortunate enough to witness the birth of nine babies from a large female that I purchased specifically because I suspected that she was “expecting.” Immediately upon emerging the offspring began to swim about the tank. Attached to the base of each baby’s skull was a white membrane about 3 inches long and 1 to 1 1/2 inches wide that fanned out behind the animal as it swam. They looked for all the world like the amphibian version of Superman “flying” around their tank!
Since these animals are imported their life span can only be surmised. I have seen figures ranging from five to twenty years. Part of this discrepancy can probably be attributed to husbandry. A well kept animal always lives longer than a poorly kept one.
The fact that they are imported implies other problems. There is no known animal that does not harbor some type of known parasite in the wild. I found this out the hard way when I came in to look at my worm in his tank and the entire bottom of the aquarium was littered with what looked like glass splinters. Examination with a microscope showed that the splinters were actually nematodes (roundworms), and from the appearance of my female it looked as though they had made a mass exodus by burrowing out through the skin. The female perished soon after. Amphibians can be tricky to medicate, but it may be worth considering if you want to keep these animals for a long time. The stress of captivity combined with the stress of birth probably weakened the female’s immune system enough to allow an explosion in her “native” population of parasites.
Caecilians are interesting and unusual animals. As common as they are relatively little is known about them. If you are looking for something different, or if you are looking for an animal that will provide you the opportunity to uncover some new information for the field of herpetology, try a worm!
by Glen Schulte