The kuhli loach (Pangio kuhlii) is a small eel-like freshwater fish belonging to the loach family(Cobitidae). They originate from Indonesia and the Malay Peninsula. This snake-like creature is very slender and nocturnal. In an aquarium, the kuhli loach can be very reclusive and, when startled, will dart underneath tank ornaments or bury itself, if a fine gravel or sandy substrate is present.
The kuhli loach is an eel-shaped fish with slightly compressed sides, four pairs of barbels around the mouth, and very small fins. The dorsal fin starts behind the middle of the body, and the anal fin well behind this. The eyes are covered with a transparent skin. The body has 10 to 15 dark brown to black vertical bars, and the gaps between them are salmon pink to yellow with a light underside. When the fish is not actively breeding, distinctions between males and females are not readily apparent. However, close observation will reveal that males have more a muscular upper/dorsal cross-section and their pectoral fins tend to be larger, more paddle-shaped, and often have some pigment in them. When breeding, the females often become larger than the male and their greenish ovaries can be seen through the skin before spawning. Spawning is not easy, but when it occurs a few hundred greenish eggs are laid among the roots of floating plants. Kuhli loaches reach maturity at 2 ¾ inches (7 cm) and have a maximum length of 4 inches (10 cm). This fish can live for up to about 10 years.