Keeping File Snakes
There are three species of Elephant Trunk, Wart, or File Snakes. Acrochordus javanicus is found in brackish to freshwater coastal waters throughout Malaysia, reaching China, Thailand, and Cambodia. Acrochordus arafurae is found in shallow freshwater in the Northern Territory and Queensland, Australia, and in Papua New Guinea. Chersydrus (formerly and perhaps occasionally disputed as Acrochordus) granulatus is found along the coasts of India, Indochina, Sri Lanka, parts of the Philippines, and Indonesia and is found in more marine habitats than the other two species, although occasionally can be found in fresh or brackish water.
I've not yet kept these species, but have come across a few articles on them. Most of what I've read states that you can keep these snakes in large tanks with relatively shallow water, up to 3 feet deep for large individuals. (Keep in mind that female A. javanicus can can probably reach eight feet in length.) Miller (1992) suggests a minimum of 10 inches for C. granulatus, which only reaches about three feet in length. There is some controversy as to whether you need to make the water brackish (using for example, commercial marine aquarium products) for the two Acrochordus, but it is definately recommended for Chersydrus. Miller used a ratio of one tablespoon of marine aquarium salt per gallon.
The cage should be large, warm (about 80° F), and contain hiding places. The water should also be well aerated. I might suggest using some "Java grass," a thin grass-like plant that does well in aquariums, though I don't know whether it would last in brackish water. The cages must be sealed tightly, as these snakes will attempt to escape. Obviously, water quality must be maintained with a filter and partial water changes.
These are live fish feeders, and apparently use their sense of touch to capture prey rather than scent or visual cues (see Miller's fascinating article). The skin appears to be crucial to the health of the animal, and should not be subjected to prolonged exposure to a dry environment. Lillywhite and Sanmartino (1993) found that C. granulatus created a "film" of water on its skin when trapped in drying pools, but it's doubtful these can last for long periods of time.
These snakes are fascinating to see, though they may remain motionless for long periods, even under water. Hopefully, more will become established in breeder's collections. Cox (1991) mentions that A. javanicus can have from 18 to 48 live young at a time, though Murphy suggests that females may only reproduce every 3 years or so in the wild. Miller found these to be hardy snakes when kept correctly and acclimated. This is a "watch but don't touch" snake, which is just as well, as many texts mention that it can give a very nasty bite.