Red-tailed Black Shark

Defined by its shark-like movements and deep black body, the Red-tailed Black Shark is a member of the carp family. This active swimmer is easily identified by its bright red tail, which contrasts against its dark, elongated frame. Mature individuals reach lengths of 6 to 8 inches, developing deeper midsections as they age. While most fins are black, the forked tail is a vivid red that can fade if the fish is unwell or stressed.

This species is native to Thailand, specifically the river systems of the Chao Phraya, Bangpakong, and lower Mae Khlong. It favors lowland streams and rivers characterized by high water flow and rocky or sandy floors. These fish are largely nocturnal and spend their time patrolling the bottom of the water column. They are omnivorous scavengers, consuming insects, worms, and plant matter, as well as grazing on algae found on rocks and vegetation.

In the wild, these fish are solitary and highly territorial. They are famously intolerant of their own species and will aggressively chase or harass fish that enter their space. Natural breeding is poorly understood, and reproduction in captivity often requires hormone injections, which can lead to high mortality rates. Wild populations are currently threatened by habitat degradation, including the building of dams and the drainage of swamps. Agricultural runoff and domestic pollution also pose significant risks to their remaining river habitats.