To the normal eye, a Caecilian Typhlonectes is the only truly aquatic genus. The members hardly use their lungs for breathing. Instead, their skin is extremely wrinkled and folded, with small pockets in the surface. These pockets pick up any air that is needed by the animal directly from the air or water and about every 20 minutes or so, it takes a big gulp of air.
Aquatic Caecilians are sold by many common names. The most common of these are "Caecilian Eels", "Caecilian Worms", "Skin Eels", "Black Worms" and "Rubber Eels."All these refer to one caecilian, Typhlonectes natans. T. natans comes from fast-flowing rivers in the Amazon River basin. It uses its cloaca (vent), as a suction cup to hold on to the bottom in rivers and streams. In the aquarium, however, it only uses it when swimming against the glass.
Aquatic Caecilians are hardy creatures that only require a few conditions. First, it needs about 3 inches of air above the waters surface. Second, the tank lid should fit perfectly on the tank and any holes or crevices should be sealed up with duct tape or something. The lid should be anchored down also for these eels can escape very easily, that's how I lost some of mine. That's all the requirements for this creature.
Water conditions are the same as for any tropical fish. Keep the temperature around 70°–75°F., the pH at about 6.5–7.5, and the hardness is not a problem. Also, you should have lots of gravel for the eel to burrow into. No lighting requirements, but keep it low if you want to see your eel very often.
You can feed Typhlonectes just about any meaty food. It is especially fond of earthworms, black worms, feeder guppies and mollies, chopped clam and prawn, and just about anything else. It is mainly a scavenger.
Caecilians are peaceful and docile, not harming any fish larger than a baby livebearer. They are livebearers and produce 5/8" young. They grow to 18–21 inches and about an inch wide.
Caecilians are only available seasonably, so don't suppose it will always be there, because it won't. Early March is the best time to find one, because huge shipments come in at that time. Hold yourself to one or two of then.
Caecilians make good pets with their childish grin and their worm-like appearance. They are a good thing to have in any aquarium.