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. 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

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. 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. 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 and will eat anything, including fish flakes, sinking wafers, and certain types of algae, just like all the sharks in this list.

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 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 gorgeous centerpiece fish grows to 5-6inches (13-15cm) and is very similar in appearance to the red tail shark. However, instead of being almost all black, they have more of a dark gray coloration with both red fins and a red tail. 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.

Although rainbow sharks are socialized more as juveniles than adults, they eventually become aggressive towards their own species. 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 roseline shark gets its common name from the shorter red line that lies on top of a longer black, horizontal stripe down the middle of its body. 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 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. 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 Eating

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. It can eat blackbeard algae as well as other types of alga and fish food leftovers. 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. You may have to fast the adults for a week in order to encourage them to eat algae.

The SAEs are found in rivers and floodplains throughout Southeast Asia. They can survive in pH levels of 6-8 and tropical temperature ranges of 72-79degF (22 to 26 degC). 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 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. As residents of Southeast Asian rivers and lakes, they are hardy enough to live in pH between 6-8 and temperature from 72-82degF (22-28degC). 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. You need to allow them plenty of space. It is difficult to find an aquarium that has at least six feet (1.8m) of length for this giant fish. Many hobbyists end-up only getting one bala shark for their 125-150-gallon fish tank. They can be kept together with similar-sized, semiaggressive fish such as cichlids and catfish.

If you’re serious about keeping a freshwater shark in your tank and making sure it has the right tank size, tank mates and other necessities, we recommend that you check out our list. All the best with your aquariums. Enjoy nature every day.