Redtail Sharkminnow

Epalzeorhynchos bicolor, commonly known as the Red-tailed Black Shark or Red-tail Shark, is a freshwater cyprinid fish native to Thailand's Chao Phraya River basin. Despite its common name, this species is not a true shark but rather a member of the carp family. The fish is characterized by its distinctive black body and bright red or orange tail fin, making it easily recognizable.

Adults typically reach lengths of 12-15 centimeters and inhabit rocky areas of rivers and streams with moderate to fast-flowing water. The species has experienced severe population decline in its native range, leading to its classification as Critically Endangered by the IUCN. Primary threats include habitat destruction through dam construction, water pollution from agricultural runoff and industrial activities, and over-collection for the aquarium trade.

The construction of dams has particularly impacted the species by altering natural water flow patterns and fragmenting populations. While the species remains popular in the global aquarium trade and is bred commercially in captivity, wild populations continue to face significant pressure. Conservation efforts have been limited, though some local initiatives focus on habitat protection and water quality improvement in remaining suitable areas.

The species' survival in the wild depends on addressing the multiple anthropogenic pressures affecting Thailand's freshwater ecosystems and implementing effective population monitoring and habitat restoration programs.

This species inhabits rocky areas of rivers and streams in the Chao Phraya River basin of Thailand, preferring areas with moderate to fast-flowing water. The fish typically occupies bottom areas near rocks and other hard substrates in freshwater environments.