Top 5 Freshwater Sharks for Aquariums (and how Big They Really Get)


Top 5 Freshwater Sharks for Aquariums (and How Big They Really Get)

You may have gone to the pet store and seen some freshwater fish labeled as “sharks.” These species are not true sharks but rather are members of the Cyprinidae family of carp and minnows. Because of their pointy fins and slender bodies, they look like sharks. Beginners often buy freshwater sharks because of their attractive shape and hardiness, but they can grow much bigger than expected and have large tank requirements in adulthood. Before you buy that cute 5-inch (5 cm) shark from the pet shop, let’s find out about their needs and decide if they are right fish for you.


1. Red Tail Shark

Epalzeorhynchos bicolor

Also known as the red-tailed black shark or redtail sharkminnow, this species is easily identified by its entirely black body and fins with a bright red tail. While they may be sweet and small as a juvenile at the fish store, an adult red tail shark grows up to 5-6 inches (13-15 cm) and requires an aquarium that’s at least 4 feet (1.2 m) long. They come from Thailand’s rivers, streams, and floodplains during the rainy season, which means they are accustomed to living in a wide range of pH between 6-8 and temperatures from 72-79degF (22-26degC). They are omnivores like the other sharks. They will eat any food, even sinking wafers or fish flakes.

Red-tailed sharks are not social creatures. As such, as they age, they become more territorial towards other sharks and members of their species. They are comfortable with semi-aggressive, similar-sized fish, such as African and South American cichlids. They can be paired with smaller, faster-schooling fish like barbs or giant danios. Avoid tank mates who are calm fish, slow swimmers, and nano creatures that could potentially be eaten.

2. Rainbow Shark

Epalzeorhynchos frenatus

This gorgeous centerpiece fish grows to 5-6inches (13-15cm) and is very similar in appearance to the red tail shark. Instead of being nearly black, they are more gray with red tail and red fins. You can also find different colors in pet shops, such as the Glofish or albino versions. They come from Thailand, as well as other Southeast Asian countries. Their pH ranges from 6.5 to 8.2 and their temperature ranges from 72-80degF (22-25 degC). They love all types of fish food, including pellets, wafers and blanched vegetables, as well as frozen foods. They will also eat algae if they are hungry.

Rainbow sharks can be more social than juveniles but they become more aggressive towards other species as they age. Consider only keeping one rainbow shark per every 4 feet (1.2 m) of aquarium length. Rainbowfish, loaches, gouramis and cichlids of similar size are all suitable roommates. But be prepared to remove certain tank mates if it doesn’t work out and the rainbow shark keeps bullying them.

3. Roseline Shark

Sahyadria denisonii

The common name of the roseline shark is the shorter red line, which lies on top of a longer horizontal black stripe running down the middle. Denison barbs are also called this species. They can reach 4-5 inches (10-13cm), and have beautiful yellow-black markings on their tail. They can be found in rivers and streams in India, with dense vegetation at the banks. They are a schooling fish that requires 3-5 people to keep them happy. A tank should be at least 4 feet in length (1.2 m) and larger. They are a peaceful and smaller fish that would be great with rainbowfish and larger livebearers. They will be happy to eat a variety of frozen, prepared, freeze-dried, gel and other foods.

4. Siamese Algae Eater

Crossocheilus sp.

Do you need an algae eater to cover larger tanks? You can try the Siamese algae eater (SAE), which has a silvery brown body with a bold, black line down its sides. This fish will eat both black beard algae and leftover fish food. Because they are larger than the adults, juveniles tend to eat more algae. You may have to fast the adults for a week in order to encourage them to eat algae.

SAEs come from rivers and floodplains in Southeast Asia and can easily live in pH of 6-8 and tropical temperatures of 72-79degF (22-26degC). You can keep a few of them around if you need a lot of algae-eating capacity for large aquariums. However, their territorial behavior towards other sharks (including their own species) is a problem. You could keep one of them in a 50-gallon aquarium or larger. They will be content living alone.

5. Bala Shark

Balantiocheilos melanopterus

The longest shark on our list is 12 inches (30cm) in length. Also known as the silver shark or tricolor shark, it has a silvery body and light-colored fins with thick, black edging. They are able to survive in a pH range of 6-8 and temperatures between 72-82degF (22-24 degC) as they live near rivers and lakes in Southeast Asia. They are easy to care for and will eat all floating and sinking foods as well as invertebrates such as shrimp and snails.

Because of its large tank size, we do not recommend this species to aquarists. Because they are constantly moving, you will need to give them enough space. Because they are a huge fish, they prefer a school of at least four fish. It can be difficult to obtain an aquarium with at minimum 6 feet (1.8 m) in size. This is why many hobbyists only get one bala Shark for a 125-to 150-gallon fish tanks. They can be kept together with similar-sized, semiaggressive fish such as cichlids and catfish.

If you are serious about providing for a freshwater shark and ensuring it has the right tank size and tank mates, consider checking out our list of preferred retailers to buy fish online. All the best with your aquariums. Enjoy nature every day.