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. Beginners often buy freshwater sharks because of their attractive shape and hardiness, but they can grow much bigger than expected and have large tank requirements in adulthood. 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
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). 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. 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 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 comfortable with semi-aggressive, similar-sized fish, such as African and South 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
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. Pet shops often sell different colors, including the Glofish and albino 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 love all types of fish food, including pellets, wafers and blanched vegetables, as well as 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. Keep one rainbow shark per 4 feet (1.2 m). Aquarium length. Suitable roommates include similar-sized cichlids, loaches, gouramis, and rainbowfish. But be prepared to remove certain tank mates if it doesn’t work out and the rainbow shark keeps bullying them.
3. Roseline Shark
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. 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. They will be happy to eat a variety of frozen, prepared, freeze-dried, gel and other foods.
4. Siamese Algae Eater
Need an algae eater to cover bigger tanks? You can try the Siamese algae eater (SAE), which has a silvery brown body with a bold, black line down its sides. 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. 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. They are content with living a solitary life, so you could consider keeping just one in a 50-gallon tank or larger.
5. Bala Shark
The largest shark on our list reaches 12 inches (30 cm) in size. 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 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. Because they are constantly moving, you will need to give them enough 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 with other similar-sized, semi-aggressive fish like larger cichlids, catfish, loaches, and gouramis.
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. Best of luck with your aquariums and enjoy nature daily.