Epalzeorhynchos” is a genus name in the family Cyprinidae, which includes a variety of freshwater fish species. This genus is notable for containing species that are popular in the aquarium trade due to their unique color patterns and active behaviors. The species within this genus are often referred to by common names such as the Red-tailed Black Shark, Rainbow Shark, and Flying Fox Fish.

1 Epalzeorhynchos bicolor, or the Red-tailed black shark, is a freshwater fish characterized by a dark black body and a bright red tail. The Red-tailed Black Shark, is a freshwater fish that belongs to the family Cyprinidae, which includes carps and minnows. Native to Thailand, these fish are unfortunately considered critically endangered in the wild due to habitat loss. However, they’re popular in the aquarium trade. It is notable for its striking color contrast. It has a dark black or deep grey body with a vibrant red tail, hence its name. The fish has a streamlined, elongated body and can grow up to 6 inches (15 cm) in length. Its mouth is surrounded by a pair of short barbels, which are sensory organs used for detecting food and navigating their environment.

Epalzeorhynchos bicolor, Red-tailed black shark

2 Epalzeorhynchos frenatum, known as the Rainbow shark, has a dark body with red or sometimes orange fins. the Rainbow shark is a popular freshwater aquarium fish. It is native to Southeast Asia, where it inhabits rivers and streams. The rainbow shark is a slender, elongated fish with a pointed snout. It has a greenish brown body with a black blotch at the base of the caudal fin. The dorsal, anal and pelvic fins are red with slightly dusky black color. The rainbow shark can grow to a length of 12 inches. It is a peaceful fish that is suitable for community aquariums. However, it should not be kept with small, delicate fish. The rainbow shark is an omnivore and will eat a variety of foods, including flakes, pellets, live food and frozen food.


3. Epalzeorhynchos kalopterus is commonly called the Flying fox fish. The Flying Fox fish is known for its sleek, elongated body that can grow up to 6 inches (15 cm) in length. It has a brownish body with a distinctive black stripe running from its mouth to the tail. The belly is usually a lighter color, and the fins are mostly transparent with a yellowish tint. The mouth has two pairs of barbels, which are sensory organs that help the fish locate food in murky water or at night. The Flying Fox fish found in Southeast Asia, specifically in Indonesia, Borneo, Sumatra, and the Malay Peninsula. They are part of the family Cyprinidae, the carps and minnows.

4. Epalzeorhynchos munense also known as the redfin shark, is a species of cyprinid fish found in the Mekong, Chao Phraya and Mae Klong rivers basins in Indochina. It resembles the rainbow shark (E. frenatum) and the two have frequently been confused (the name red fin shark has been used for both). Unlike other Epalzeorhynchos species, E. munense is believed to be rare in the aquarium trade and is not known to be bred in commercial farms.

Please note that while these fish are often referred to as “sharks” due to their shark-like dorsal fins and overall body shape, they are not true sharks. They are a type of cyprinid, related to carps and minnows.

Selecting the Right Aquarium

When it comes to housing Epalzeorhynchos, tank size matters. These fish are active swimmers and need ample space to move around. A tank of at least 30 gallons is recommended for one fish, with an additional 10 gallons for each extra fish. The aquarium should be wider than it is tall, as these species are known to swim more horizontally than vertically.

Creating the Ideal Environment

Epalzeorhynchos prefer a habitat that resembles their natural environment. They appreciate a tank with plenty of hiding places, so consider using rocks, driftwood, and aquatic plants to create a natural, river-like environment. However, ensure that the materials used do not have sharp edges as they could harm the fish.

The substrate should be soft, as Epalzeorhynchos species are bottom dwellers and often sift through the substrate. Sand or small, smooth gravel is ideal. They also prefer dim lighting, so consider using subdued lighting or providing plenty of shade with plants and decor.

Red Tail Shark

Water Conditions

As tropical freshwater fish, Epalzeorhynchos thrive in warm, slightly acidic to neutral water. Maintain a temperature between 72 to 79 degrees Fahrenheit and a pH level between 6.5 to 7.5. Regular water changes are crucial to keep the nitrate levels low and maintain water quality.

Aquarist Experience Level: Moderate
Minimum Tank Size: at least 55 gallons
Care Level: Moderate
Behaviors: semi-aggressive fish.
Water Conditions: 72° to 80° F, pH 6.5 -7.6
Size: normally 6 inches.
Lifespan: 5-6 years
Diet: Omnivore


Epalzeorhynchos are omnivorous and have a varied diet. Feed them high-quality flake food or pellets as a basic diet, supplemented with fresh, frozen, or freeze-dried foods such as bloodworms, brine shrimp, and vegetables. Avoid overfeeding, as this can pollute the water and lead to health problems.

Behavior and Compatibility

Epalzeorhynchos species are known for their territorial behavior, especially among their own kind. It’s advisable to keep only one Epalzeorhynchos per tank to avoid conflicts. They can cohabitate with other species that occupy different areas of the tank and are not too small to be seen as prey.


Epalzeorhynchos are generally hardy fish, but they are not immune to common fish diseases like ich or fin rot. Regular monitoring of fish behavior and water conditions is essential to detect early signs of illness.


Breeding Epalzeorhynchos in an aquarium is extremely challenging, and there’s little documentation of successful captive breeding. Most Epalzeorhynchos sold in pet stores are wild-caught or bred in commercial farms using hormones.

In conclusion, Epalzeorhynchos are striking, active fish that can be a joy to keep in an aquarium. While they require some specific care requirements, their lively nature and fascinating behavior make the effort worthwhile. With the right care, these fish can live up to 10 years, providing a long-term companionship for the dedicated aquarist.

Please note: This article isintended to be a guide and does not replace professional advice. It’s important to do further research and consult with a local aquarist or pet store to ensure the best care for your Epalzeorhynchos.

By fishexp