Epalzeorhynchos bicolor
Jet-black body with a fire-red caudal fin, one of the most striking community fish you can buy. Strictly one per tank: they don't tolerate their own kind or anything else with a similar silhouette (rainbow shark, SAE, bottom-dwelling barbs). Wild populations are functionally extinct; every fish you see is commercially bred in Thailand.
Red-Tailed Black Shark (Epalzeorhynchos bicolor) reaches 12–15 cm as an adult and needs a minimum tank of 200 L. Native to Thailand (Chao Phraya basin), critically endangered in the wild, it lives in the bottom to mid water column with a territorial temperament. Aim for 22–26 °C, pH 6.5–7.5, and 5–15 dGH hardness. Lifespan is 6–8 years with good care. Red-Tailed Black Shark can be kept singly or in a small group. Diet: omnivore (heavy on algae and plant matter), Sinking wafers, blanched veg, algae sheets. Will also take pellets and frozen foods. Plant-safe: Yes (mostly). Shrimp-safe: No (will hunt).
Care at a glance
Jet-black body with a fire-red caudal fin, one of the most striking community fish you can buy. Strictly one per tank: they don't tolerate their own kind or anything else with a similar silhouette (rainbow shark, SAE, bottom-dwelling barbs). Wild populations are functionally extinct; every fish you see is commercially bred in Thailand.
By Mike ElmiraUpdated 1 min read
Part of our complete guide to aquarium fish for the planted tank.
The parameters that decide whether red-tailed black shark fits in your tank.
Bottom to Mid
No
Can be kept solo
Cyprinidae
Omnivore (heavy on algae and plant matter)
Sinking wafers, blanched veg, algae sheets. Will also take pellets and frozen foods.
6–8 yrs
Very Hard
Clear forest streams of central Thailand (extinct in the wild)
Thailand (Chao Phraya basin), critically endangered in the wild
Tank-mate safety and the species this one is documented to thrive (or fail) alongside.
Direct answers to the questions search engines and AI assistants surface most often about this species.
Red-Tailed Black Shark (Epalzeorhynchos bicolor) needs a minimum tank of 200 L. They live in the bottom to mid water column and can be kept singly, so a longer footprint matters more than depth.
Target 22–26 °C, pH 6.5–7.5, and 5–15 dGH hardness. Acclimate slowly when moving them between water sources.
Shrimp safety: No (will hunt). Plant safety: Yes (mostly).
Red-Tailed Black Shark are omnivore (heavy on algae and plant matter). Sinking wafers, blanched veg, algae sheets. Will also take pellets and frozen foods.
On Fin & Stem's 1–5 difficulty scale this species rates 3/5. Intermediate, stable parameters and a mature tank matter. Breeding difficulty: very hard.
Typical lifespan in a well-maintained tank is 6–8 years.
A planted tank is a system. Pair this fish with one entry from each other pillar to plan the whole scape.
