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. They just happen to look like sharks because of their slender, torpedo-shaped bodies and pointy fins. 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. Let’s take a look at their requirements before we buy that 2-inch (5-cm) shark at the pet shop.

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. 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). Like all of the sharks on this list, they are omnivores that will eat almost anything – including sinking wafers, fish flakes, and even certain types of algae.

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 pair them with super-fast schooling fish such as giant danios or barbs. Avoid tank mates that are peaceful fish, slow swimmers, or nano creatures that could 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. Plus, pet stores commonly sell different color variations, such as the albino and Glofish versions. They also come from Thailand and nearby Southeast Asian countries and can live in a broad gamut of pH levels between 6.5-8.0 and temperature from 72-80degF (22-27degC). They are fond of eating all kinds community fish foods, such as pellets, wafers or blanched vegetables. They will also eat algae if they are hungry.

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

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. 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 are native to fast-moving rivers in India and have dense vegetation close to the banks. They would thrive 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. 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.

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. They tend to eat more algae as juveniles because the adults are large enough to get the lion’s share of the fish food you feed. 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 can live in temperatures between 72-82degF and 72-82degC as they are native to Southeast Asian rivers or lakes. 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. They are constantly on the move, so you need to provide adequate swimming space for this foot-long creature. 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 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.