Red Tail Shark

Geographic Origin and Biotope: Endemic to the Chao Phraya river basin in Thailand. Historically considered extinct in the wild (EW) since 1996 due to dam construction and agricultural pollution, small relic populations were recently discovered in the Mae Klong river basin. Inhabits slow rivers and floodplains shaded by dense vegetation.

Taxonomy and Morphology: Member of the Cyprinidae family. Possesses a cylindrical and hydrodynamic body, clearly designed for benthic swimming. It features an inferior mouth equipped with two pairs of barbels, adapted for scraping biofilm. Reaches 15 cm (6 inches) in length, appearing compact and robust.

Social Behavior: Markedly territorial and solitary as an adult. Extremely aggressive and intolerant toward its own kind (conspecifics) and fish of similar shape or color (like other river "sharks" or labeos). It spends its existence guarding a favorite refuge (cave or root) from which it chases away anyone who approaches.

Coloration and Sexual Dimorphism: Unmistakable and dramatic livery: deep, velvety solid black body, interrupted by a highly vivid fire-red caudal fin. In juveniles, other fins may have pale margins. Adult females are slightly more massive and round-bellied; males remain sleeker but show no obvious chromatic differences.

Aquarium Setup: Requires aquariums at least 120 cm (4 feet) long. The presence of numerous blind refuges is mandatory: hidden PVC pipes, dense root tangles, and crevices between smooth rocks. Subdued lighting and floating plants limit stress. Well-oxygenated and filtered water, soft sand substrate to avoid damaging barbels.

Diet and Feeding: Omnivorous scavenger. In the wild, it grazes on algae, epilithic biofilm, and small benthic invertebrates. In the aquarium, it accepts everything: sinking pellets, bottom feeder tablets, bloodworms, and fresh vegetables (zucchini and peas). A strong vegetable component is vital to prevent intestinal disorders and maintain the intensity of the black.

Water Quality: Very robust if properly acclimated. Prefers soft to medium waters (GH 5.0-15.0), pH 6.5 to 7.5, and temperatures of 22.0-26.0 °C (72-79 °F). Highly susceptible to sudden temperature swings and nitrogen spikes, which cause a rapid fading of the black to an ash gray, indicating extreme distress.

Compatibility and Tankmates: Strict. Must be kept strictly AS A SINGLE specimen per tank to avoid fights to the death. Coexists well with robust schooling fish that swim in the upper part of the aquarium (Barbs, Danios, Rainbowfish). Absolutely avoid shy Corydoras or Loaches, which would be relentlessly harassed and fatally stressed at the bottom.

Aquarium Reproduction: Virtually impossible in private tanks due to intraspecific violence. All commercially available specimens worldwide derive from colossal aquaculture farms in Southeast Asia (or Eastern Europe) where gravid females are mechanically induced to spawn via hormone injections.

Risks and Diseases: Strong propensity to jump out of the aquarium if spooked or placed in small tanks without adequate refuges (lid mandatory). Frequently suffers from Ichthyophthirius (Ich) due to thermal shock during water changes. Increasing aggression with age often leads inexperienced owners to have to rehome it.