穴条鳅

Overview

Nemacheilus troglocataractus is a highly localized cave loach with no body pigmentation and usually no externally visible eyes. It is best understood as an example of subterranean adaptation and habitat conservation, rather than as an ordinary aquarium fish.

Distribution & habitat

It is known only from the Tham Sai Yok Noi cave system in Kanchanaburi, Thailand. The cave stream belongs to the Khwae Noi drainage of the upper Mae Klong. Several local names refer to the same cave system, rather than separate populations.

The habitat is entirely underground, with bedrock and some gravel in shallow areas. A relatively slow stream connects numerous small pools. Fish have been observed both on rocks in oxygenated flowing water and in pools. Surveys found few individuals, but neither the cave's full extent nor population size can be established from those limited observations.

Diet & feeding

The natural diet is unconfirmed, though bottom-dwelling invertebrates are thought likely to dominate. This does not establish a tested aquarium feeding regime.

Behaviour & compatibility

Captive observations suggest some territorial behavior and aggression between individuals. Dominant fish may swim in a zigzag pattern, shove others with the side or underside of the body, and bite. Reduced vision does not imply an absence of conflict.

Notes

Most individuals lack visible eyes, although a residual eye on one side has been observed in at least one specimen. Its underground adaptations should not be equated with the lifestyle of ordinary stream loaches. A known range limited to one cave system makes habitat protection particularly relevant.