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. Their slender bodies and pointed fins make them look like sharks. Although they are attractive and tough, beginners often purchase freshwater sharks due to their hardiness and attractive shape. However, adult freshwater sharks can grow very large and require large tanks. 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

The red-tailed red sharkminnow is also known as the red tail sharkminnow. This species can be easily identified by its completely black body, fins and bright red tail. Although they are small and sweet as juveniles, adult redtail sharks can grow up to 5-6 inches (11.3-15 cm). They require an aquarium at least 4 feet long (1.2m). They are native to Thailand’s streams, rivers, and floodplains in the rainy season. This means that they can tolerate temperatures between 72-79degF (22-25 degC) and a range of pH levels. They are omnivores like the other sharks. They will eat any food, even sinking wafers or fish flakes.

Red tailed sharks are solitary creatures and not schooling fish, so as they grow older, they become very territorial towards members of their own species and other sharks. They are able to live with other semi-aggressive fish of similar size, such as African cichlids and South and Central American Cichlids. You can pair them with super-fast schooling fish such as giant danios or barbs. Avoid tank mates who are calm fish, slow swimmers, and nano creatures that could potentially be eaten.

2. Rainbow Shark

Epalzeorhynchos frenatus

This magnificent centerpiece fish can grow to 5-6 inches (11.3-15 cm) in length and is very similar to the red-tail shark. Instead of being nearly black, they are more gray with red tail and red fins. Plus, pet stores commonly sell different color variations, such as the albino and Glofish versions. They are also from Thailand and other Southeast Asian countries. They can live in temperatures between 72-80degF (22 to 27 degC) and pH levels between 6.5 and 8.2. They enjoy eating all kinds of community fish foods like pellets, wafers, blanched veggies, and frozen foods. When they feel hungry, they will often eat alga when available.

While rainbow sharks are more social as juveniles, they eventually become semi-aggressive towards their own species and other sharks. Consider only keeping one rainbow shark per every 4 feet (1.2 m) of aquarium length. You can find suitable roommates in rainbowfish, loaches and gouramis as well as cichlids, loaches and gouramis that are similar in size. If it does not work out, or the rainbow shark continues to bully them, be ready to get rid of certain tank mates.

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. They are also known as Denison barbs and can grow up to 4-5 inches (10-13cm) in length. Their tails have beautiful yellow and black markings. They come from fast-moving rivers and pools in India with dense vegetation near the banks and would appreciate living in a planted aquarium. They are schooling fish, and will require at least 3-5 fish to be in their group. Therefore, a tank of 4 feet (1.2m) or more is recommended. As one of the smaller and more peaceful fish on this list, they would do great with rainbowfish, bigger livebearers, and other fast swimmers. They will be happy to eat a variety of frozen, prepared, freeze-dried, gel and other foods.

4. Siamese Algae eater

Crossocheilus sp.

You need an algae eater that can 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. It is one of the few fish that will eat black beard algae, as well as other types of algae and fish food leftovers. Because the adults are larger, they tend to consume more algae than the juveniles. To encourage the adults to go after algae, you may need to fast them for about a week to get them hungry enough.

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). Although you could get them in a group if you have a lot of algae-eating power, they can become territorial towards other sharks as well. They can live a simple life and are happy to be kept alone in a 50-gallon or larger tank.

5. Bala Shark

Balantiocheilos melanopterus

The largest shark on our list reaches 12 inches (30 cm) in size. 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 quite easy to feed and will readily eat any floating or sinking foods, as well as invertebrates like 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. As a giant fish that prefers a school of four or more, it can be hard to get an aquarium with at least 6 feet (1.8 m) in length, so many hobbyists end up just getting one bala shark for a 125- to 150-gallon fish tank. 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. Best of luck with your aquariums and enjoy nature daily.