Red Tail Shark

Also known as: Epalzeorhynchos bicolor

The Red Tail Shark is a striking freshwater fish known for its jet-black body and vivid red caudal fin, resembling a miniature shark. The Red Tail Shark originates from Native to the Chao Phraya and Mekong river basins in Thailand and Cambodia, inhabiting fast-flowing, rocky streams with clear, well-oxygenated water., reaches Adult size: 15 cm in captivity, typically lives 5–8 years, and is kept at 22–26°C (72–79°F). Individual fish vary, so treat this as a general guide rather than a guarantee.

Species at a glance

Origin: Native to the Chao Phraya and Mekong river basins in Thailand and Cambodia, inhabiting fast-flowing, rocky streams with clear, well-oxygenated water.
Adult size: Adult size: 15 cm (6 inches)
Life span: 5–8 years
Temperament: Semi-aggressive and territorial, especially toward conspecifics and similarly shaped bottom-dwellers; best kept singly or with robust, fast-moving tankmates.
Tank size: Minimum 150 liters (40 gallons)
Water temp: 22–26°C (72–79°F)
pH range: 6.5–7.5
Diet: Omnivorous; accepts high-quality sinking pellets, algae wafers, blanched vegetables (zucchini, spinach), and occasional live/frozen foods like bloodworms, brine shrimp, and daphnia.
Other names: Epalzeorhynchos bicolor

About the Red Tail Shark

The Red Tail Shark is a striking freshwater fish known for its jet-black body and vivid red caudal fin, resembling a miniature shark. Despite its name, it is not a true shark but a member of the carp family (Cyprinidae). It is an active bottom-dweller that constantly forages for food and explores its environment. In captivity, it requires ample space and hiding spots to reduce stress and territorial aggression.

Lifespan and health

With optimal care, Red Tail Sharks typically live 5–8 years in captivity, though exceptional individuals may reach 10 years. Lifespan is heavily influenced by tank size, water quality, diet, and stress levels; chronic aggression from tankmates or inadequate space significantly shortens longevity. Common health issues include ich (white spot disease) due to stress or poor water conditions, fin nipping from aggressive tankmates leading to secondary infections, and obesity from overfeeding or lack of exercise. Parasitic infections like gill flukes and internal nematodes are also possible if new fish are not quarantined. Regular observation for lethargy, loss of color, clamped fins, or abnormal swimming is critical for early intervention.

Overview

Care and tank setup

Tank setup should include a sandy or fine gravel substrate with plenty of hiding places such as driftwood, rock caves, and dense planting (e.g., Anubias, Java fern) to break lines of sight. A minimum tank length of 120 cm (47 inches) is recommended to accommodate its swimming needs. Strong filtration and moderate to high water flow mimic its natural riverine habitat, and a tight-fitting lid is essential as it is known to jump. Water parameters must be stable: maintain temperature between 22–26°C (72–79°F), pH 6.5–7.5, and hardness of 5–15 dGH. Perform 25–30% water changes weekly to keep nitrates below 20 ppm. Avoid sudden changes in water chemistry, as this species is sensitive to poor water quality. Feed a varied diet 2–3 times daily in small amounts it can consume within 2–3 minutes. Prioritize sinking foods to ensure it gets adequate nutrition. Supplement with vegetable matter 2–3 times per week to support digestive health. Overfeeding should be avoided to prevent obesity and water degradation.

Adding a Red Tail Shark? Research the species’ adult size and temperament carefully, quarantine new fish before introducing them to your tank, and buy from reputable aquarium stores or breeders.

Breed information on this page is based on the Wikipedia article on the Red Tail Shark, supplemented with additional research. Reviewed for accuracy.