Other freshwater fish · Advanced care

Red-tail shark

Epalzeorhynchos bicolor

Red-tail shark is rated advanced here because of its adult size, water range and social needs. Use plants or wood for cover while leaving room for the school to move.

Red-tail shark (Epalzeorhynchos bicolor) in an aquarium
Photo: Astellar87 · CC BY-SA 4.0
Adult size15 cm (5.9 in)
Minimum tank55 US gal
Temperature73–82°F (23–28°C)
pH range6.5–8.0
Group sizeOne or a compatible pair
Swimming levelMiddle to upper

Is Red-tail shark a good aquarium fish?

Red-tail shark reaches about 15 cm as an adult, so plan around the adult fish rather than the juvenile size seen in shops. The suggested minimum of 55 US gallons assumes suitable filtration, open swimming space and routine maintenance.

Territorial, especially when breeding. Keep the recommended group of one fish or a compatible pair and avoid mixing it with tank mates that need a very different temperature, water chemistry or swimming level.

Water and aquarium setup

A stable temperature of 23–28°C and pH of 6.5–8.0 are the working ranges in the planner. Stability and clean, oxygenated water matter more than chasing a single target number.

Use plants, wood or rock to create cover while leaving the open swimming space this species needs.

Diet

Small community-fish pellets or flakes, supplemented with frozen or live foods.

Compatibility notes

Red-tail shark is generally workable in a community aquarium when the tank mates share its temperature range and social needs.

Use the Stocking & Bioload Planner to check a proposed community. Its estimated bioload value for one adult red-tail shark is 17.15 units; this is a planning heuristic, not a replacement for testing nitrate.

Common mistakes

  • Planning around the shop size instead of the adult size.
  • Adding a schooling fish in a group smaller than its social minimum.
  • Ignoring the tank's length, floor area or lid because the gallon number looks adequate.
  • Adding fish before the aquarium is cycled and ammonia and nitrite are consistently zero.

Care ranges are conservative summaries of commonly cited husbandry references. Individual fish, strains and local water can differ; monitor the aquarium and adjust the plan gradually.

Photo source: Astellar87 · CC BY-SA 4.0. The local copy is resized for page performance.