Product Details

Red Tailed Black Shark – Epalzeorhynchos bicolor

The Red Tailed Black Shark is a striking freshwater cyprinid known for its velvet-black body, bright red tail and bold territorial behaviour. Also sold as the Red Tail Shark, Redtail Sharkminnow, Red-tailed Black Shark or under the older name Labeo bicolor, this species is best suited to larger mature aquariums with robust tank mates, strong filtration, open swimming space and plenty of caves or visual barriers. It is not a true shark, but its confident behaviour and adult territorial nature mean it should be chosen carefully.

Key Identification:

Common Name: Red Tailed Black Shark
Other Names: Red Tail Shark, Redtail Sharkminnow, Red-tailed Black Shark, Redtail Black Shark
Scientific Name: Epalzeorhynchos bicolor
Older / Trade Name: Labeo bicolor
Fish Type: Cyprinid / Shark Minnow
Water Type: Freshwater

Natural Range & Habitat:

Epalzeorhynchos bicolor is native to Thailand, historically associated with river systems including the Chao Phraya basin. Wild habitats include mainstream rivers, floodplain waters and connected seasonal areas where the fish can graze, forage and hold territories around structure.

The species is now extremely rare in the wild, and aquarium specimens are commercially captive-bred. In the aquarium, it should be provided with a spacious layout containing open swimming room, smooth stones, driftwood, caves, shaded areas and broken lines of sight.

Appearance & Adult Size:

Red Tailed Black Sharks have a sleek, shark-like body shape with a pointed head, high dorsal fin and strong swimming posture. The body is usually deep black to charcoal, contrasting strongly with a vivid red to orange-red tail.

Adults usually reach around 12–15 cm. Young fish may appear slimmer and less territorial, but mature individuals become more confident, muscular and dominant. Colour is usually strongest in settled fish kept in clean water with a good diet and low stress.

Aquarium Suitability:

This species is suitable for larger tropical aquariums, robust community setups and semi-aggressive displays. It needs space, structure and carefully chosen tank mates.

Red Tailed Black Sharks are not suitable for small peaceful community aquariums, nano tanks or tanks with timid bottom-dwellers. They are often sold small, but they can become territorial as they mature, especially around caves, the lower levels of the aquarium and similar-shaped fish.

Recommended Aquarium Size:

A practical minimum is 200 litres for a single adult, with a tank length of at least 100–120 cm recommended. Larger aquariums are strongly preferred for community setups.

Keep one per aquarium unless the tank is very large and carefully structured. Multiple Red Tailed Black Sharks are likely to fight in most home aquariums, especially as they mature.

Water Conditions:

Temperature: 22–26°C
pH: 6.5–7.5
Hardness: Soft to moderately hard
Additional Notes: Red Tailed Black Sharks prefer clean, stable, well-oxygenated water with good filtration and regular water changes. Provide moderate flow, open swimming space and plenty of cover. Avoid poor water quality, cramped aquariums, unstable new tanks and very strong turbulent flow.

Temperament & Tank Mates:

Aquarium Category: Semi-Aggressive

Red Tailed Black Sharks are territorial bottom to mid-level fish. They are often peaceful when young, but adults may chase, dominate or harass tank mates, especially other shark-like cyprinids, loaches, similar-shaped bottom fish or smaller timid species.

Suitable tank mates include robust barbs, larger rasboras, medium rainbowfish, larger tetras, peaceful livebearers in suitable water, larger danios and sturdy catfish that are not easily bullied. Avoid tiny fish, shy bottom-dwellers, slow long-finned species, other Red Tailed Black Sharks, Rainbow Sharks, Flying Foxes and similar territorial species in most aquariums.

Feeding:

Red Tailed Black Sharks are omnivorous grazers and foragers. In the aquarium, offer quality sinking pellets, algae wafers, spirulina foods and small granules as the staple diet.

Supplement with frozen or live foods such as bloodworm, daphnia, brineshrimp, mosquito larvae and tubifex. Vegetable foods such as blanched courgette, spinach, peas and algae-based flakes are also useful. They may graze algae and biofilm, but they should not be relied on as an algae cleaner.

Behaviour in the Aquarium:

This is an active, territorial species that often patrols the lower and middle areas of the aquarium. It may claim a cave, wood pile, stone area or section of the tank and chase other fish away from it.

In a well-planned aquarium, a single Red Tailed Black Shark can become a bold centrepiece fish. Its best behaviour is usually seen in a spacious tank with plenty of cover, strong sightline breaks and tank mates that are active enough to avoid being intimidated.

Care Notes:

Plan for adult temperament, not just juvenile size. Red Tailed Black Sharks are commonly sold when small, but they need long-term space and should not be added to small community tanks.

Keep only one in most aquariums and avoid similar-shaped fish that may trigger territorial aggression. Provide caves, wood, plants and open areas so the fish can establish a territory without controlling the entire tank. Maintain excellent water quality and monitor behaviour as the fish matures.

Recommended For:

Intermediate

Availability:

Common / Usually captive-bred commercial stock

Image Disclaimer:

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Natural variation in size, colour, pattern, fin shape, body tone and markings can occur between individual fish.