The distinctive redtailed black shark was previously believed to be extinct in the wild, and was known only from captivity. The aquarium fish trade may be one of the reasons for its decline in the wild, although there is not yet any evidence to support this theory. A more likely reason for the redtailed black shark’s demise is habitat alteration; during the 1970s, numerous dams were constructed in Thailand, which probably had severe impacts on the rivers in the region. Large areas of swamps in Thailand have also been drained, destroying potential habitat for the redtailed black shark (1).
More recently, the redtailed black shark has been rediscovered in Chao Phraya, but it is only known from a single, tiny area. The major threat to the wild population is currently pollution from agricultural and domestic sources. Road building and the development of dams are also affecting its habitat and altering water flow, while agricultural activities may be causing siltation of rivers (1).