Redtail Shark (Epalzeorhynchos bicolor)

The Redtail Shark (Epalzeorhynchos bicolor) is one of the most striking contrasts in the freshwater hobby: a jet black body cut off by a blazing red-orange tail, patrolling the lower half of the tank like it owns the place, because as far as it is concerned, it does. Not a true shark but a bold, torpedo-shaped cyprinid, it makes an unforgettable centerpiece for a larger community tank when you respect its one big rule: one Redtail per tank. Our current juveniles are around 2 inches. Browse the rest of our freshwater livestock and supplies to build the tank around it.

Care Guide

• Tank size: 55 gallons or larger for an adult. Juveniles start peaceful, but a grown 6 inch fish patrols serious territory and needs room for tank mates to stay out of it.
• Water parameters: 72 to 79°F, pH 6.8 to 7.5. Hardy and forgiving once established.
• Territory: give it a cave or hollow it can claim, like the Hikari Dark Rock Cave, plus rockwork and driftwood that break up sight lines. A shark with a home base is far more relaxed.
• Feeding: omnivore and part-time grazer. Rotate sinking pellets and gel food like Repashy Community Plus with vegetable matter; it will also rasp biofilm and some algae off surfaces.
• Lid required: a strong jumper, especially when startled or newly introduced.
• Color tip: the black deepens and the tail brightens with good food, clean water, and a fish that feels secure. A washed-out Redtail is a stressed Redtail.

Specifications

Compatibility

The golden rule: one Redtail Shark per tank, and no lookalikes. It will relentlessly chase its own kind, the closely related Rainbow Shark, and similar bottom-hugging fish like the Chinese Algae Eater. Pair it instead with fast schooling mid-water fish that shrug off a chase: Zebra Danios, larger tetras like the Rummy Nose, and robust Yo Yo Loaches in bigger tanks. Skip slow, long-finned fish like fancy guppies and bettas, and avoid timid bottom dwellers that would have to share its floor.

Recommended Foods & Supplies

• Hikari Dark Rock Cave a territory to call home
• Repashy Community Plus omnivore gel food
• Repashy Soilent Green for the grazing side of its diet

FAQ

Is it really a shark?
No. It is a cyprinid, a cousin of barbs and rasboras, named for its shark-like profile and dorsal fin. It has no teeth worth worrying about and tops out around 6 inches.

Can I keep two so they have company?
No. Two Redtails in a typical home tank means one constantly harassed fish. This species genuinely prefers being the only one of its kind.

Why is mine chasing my other fish?
It is defending what it considers its territory, usually the bottom third of the tank. More sight-line breaks, a dedicated cave, and fast tank mates turn constant chasing into brief, harmless escorting.

My juvenile is more gray than black. Is it healthy?
Very likely yes. Juveniles and newly moved fish often look faded. Give it a week or two of good food and a claimed cave and the velvet black comes in.