Red-tailed black shark
Epalzeorhynchos bicolor
Care at a glance
- Temperature
- 68–79°F (20–26°C)
- pH
- 6.5–7.5
- Adult size
- 4.7 in (12 cm)
- Minimum tank
- 30 gal (115 L)
- Temperament
- Mostly peaceful
- Social behavior
- Solitary
- Swim level
- Bottom
- Difficulty
- Medium
- Breeding
- No record
- Rarity
- Common
- Origin
- Thailand
- Family
- Cyprinidae
Overview
This is a solitary, territorial fish that holds the bottom and chases off its own kind and anything that looks similar, so keep just one per tank. It does best in a larger community with active mid and upper water fish that stay out of its zone, and plenty of hiding spots to break up its territory. Feed sinking pellets, algae wafers, and the occasional frozen treat like bloodworms or brine shrimp. Good oxygen and current keep it comfortable.
In the wild
Red-tailed black sharks come from the Chao Phraya basin in Thailand, living in clear, flowing rivers and streams over rock and sand with plants and roots for shelter. In the tank they like steady flow, good oxygen, and plenty of caves and wood to claim and hide in. Keep the pH from 6.5 to 7.5 and temps in the low to mid 20s C. Give them a 115 liter tank or larger with broken-up territory.
Good to know
This is a member of the carp family, Cyprinidae, reaching about 12 cm, with a jet-black body and a bright red tail. It is an egg-layer that rarely breeds in home tanks. The IUCN lists it as Critically Endangered in the wild because of habitat loss, so nearly every fish in the trade is commercially farmed rather than wild-caught.
Did you know
Once common in Thai rivers, it was feared extinct in the wild for years before small populations turned up again, and it remains Critically Endangered. The hobby owes its supply almost entirely to farms, mostly in Southeast Asia, a rare case of aquaculture keeping a species available while its native range stays in trouble.
Where to buy
Some links may not be the exact species or variety.
…or ask your local fish store.
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Related species

Rainbow shark
Epalzeorhynchos frenatum5.9 in (15 cm)32 gal (120 L)68–79°F (20–26°C)
Flying fox
Epalzeorhynchos kalopterus6.3 in (16 cm)37 gal (140 L)68–79°F (20–26°C)
Panda Garra
Garra flavatra3.5 in (9 cm)26 gal (100 L)72–81°F (22–27°C)
Silver flying fox
Crossocheilus reticulatus6.3 in (16 cm)53 gal (200 L)64–77°F (18–25°C)
Doctor Fish
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Cambodian log sucker
Garra cambodgiensis5.9 in (15 cm)32 gal (120 L)68–81°F (20–27°C)
