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. 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. 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. 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). These sharks are native to Thailand’s rivers, streams and floodplains. They can live in temperatures between 72-79 degrees F (22-26 degrees C) and pH ranges of 6-8. They are omnivores like the other sharks. They will eat any food, even sinking wafers or fish flakes.

Red-tailed sharks live alone and are not interested in schooling fish. As they get older, their territoriality towards other sharks and their species increases. 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 also pair them with slightly smaller, super-fast schooling fish, like giant danios and barbs. Avoid peaceful fish, slow swimmers or nano creatures that could be eaten as tank mates.

2. Rainbow Shark

Epalzeorhynchos frenatus

This beautiful centerpiece fish also grows to 5-6 inches (13-15 cm) and looks very similar to the red tail shark. Instead of being nearly black, they are more gray with red tail and red fins. Pet shops often sell different colors, including the Glofish and 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 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.

Although rainbow sharks are socialized more as juveniles than adults, they eventually become aggressive towards their own species. Limit the number of rainbow sharks you keep to one per 4ft (1.2m) aquarium length. You can find suitable roommates in rainbowfish, loaches and gouramis as well as cichlids, loaches and gouramis that are similar in size. 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

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 are native to fast-moving rivers in India and have dense vegetation close to the banks. They would thrive in a planted aquarium. Unlike the previous fish on this list, they are a schooling fish and require 3-5 or more in their party, so be prepared to get a tank that is 4 feet (1.2 m) in length or greater. They are a peaceful and smaller fish that would be great with rainbowfish and larger livebearers. You should have no problems feeding them an assorted mix of prepared, freeze-dried, gel, and frozen 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. It can eat blackbeard algae as well as other types of alga 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. 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 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 can live in temperatures between 72-82degF and 72-82degC as they are native to Southeast Asian rivers or lakes. They are quite easy to feed and will readily eat any floating or sinking foods, as well as invertebrates like shrimp and snails.

This species is not recommended for aquarists due to its huge tank size requirements. They are constantly on the move, so you need to provide adequate swimming space for this foot-long creature. 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 caring for a freshwater fish shark, and making sure that it has the right size tank and tank mates to thrive, then we suggest checking out our preferred online retailers. All the best with your aquariums. Enjoy nature every day.