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. Freshwater sharks are popular among beginners due to their beautiful shape and hardiness. However, they can get much larger than expected and will require large tanks. So, before you take home that adorable 2-inch (5 cm) shark at the pet store, let’s learn about their requirements and see if they are the right fish for you.


1. Red Tail Shark

Epalzeorhynchos bicolor

This species is also known as the red-tailed sharkminnow or redtail sharkminnow. Its completely black body and fins are easily identifiable by its bright red tail. As a juvenile, they can be quite sweet and tiny. However, an adult red-tailed shark can grow to approximately 5-6 inches (13-15cm) in length and requires an aquarium of at least 4ft (1.2m) in length. 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 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. They can be paired with smaller, faster-schooling fish like barbs or giant danios. Avoid peaceful fish, slow swimmers or nano creatures that could be eaten as tank mates.

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. They are not nearly all black but have a darker gray coloration and red tail. You can also find different colors in pet shops, such as the Glofish or albino 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 love all types of fish food, including pellets, wafers and blanched vegetables, as well as frozen foods. Plus, they will opportunistically pick at algae when hungry enough.

While rainbow sharks are more social as juveniles, they eventually become semi-aggressive towards their own species and other sharks. Limit the number of rainbow sharks you keep to one per 4ft (1.2m) aquarium length. Suitable roommates include similar-sized cichlids, loaches, gouramis, and rainbowfish. However, it is possible to remove tank mates from your tank if you are not happy with the arrangement or if the rainbow shark bullies them.

3. Roseline Shark

Sahyadria denisonii

Roseline sharks are named for the red horizontal stripe that runs down its middle. It is a shorter, more prominent line of color than the longer, blacker lines. Also known as Denison barbs, they grow to 4-5 inches (10-13 cm) long and have lovely yellow and black markings on the tail. They can be found in rivers and streams in India, with dense vegetation at the banks. 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. It should not be a problem to feed them a mix of freeze-dried, gel, and prepared foods.

4. Siamese Algae Eater

Crossocheilus sp.

Need an algae eater to cover bigger tanks? The Siamese alga eater (SAE), 6-inches (15 cm) has a silvery-brown body and a bold black line running down its side. 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. In order to encourage adults to pursue algae, it may be necessary to fast them for around a week.

They are native to rivers and floodplains of Southeast Asia. They can live in pH 6-8 and tropical temperatures between 72-79degF (22-25 degC). 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. You could keep one of them in a 50-gallon aquarium or larger. They will be content living alone.

5. Bala Shark

Balantiocheilos melanopterus

Our largest shark measures in at 12 inches (30 cm). The silver shark or tricolor shark is also known. It is characterized by a silvery-colored body and fins with thick, dark 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 very easy to feed, and will happily eat floating or sinking food as well as invertebrates, such as shrimps and snails.

This species is not recommended for aquarists due to its huge tank size requirements. You need to allow them plenty of 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 with other similar-sized, semi-aggressive fish like larger cichlids, catfish, loaches, and gouramis.

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.