When I was a teenager I kept several of these freshwater sharks in a very large aquarium. As with all of my shark content, I like to give context as to how I came across these species and what I learned about them. Any kind of shark that I am going to mention in this article gets very large and is not suitable for the home aquarium unless the aquarium is a minimum of 300 to 400 gallons or more. So, with that said, here is the back story:
When I was kid my uncle had rescued a nurse shark who had been badly injured by fishing line. He rehabilitated her and kept her in a very large aquarium for a few years before she was able to be released back into the wild. She was the coolest shark that I had ever met! She was friendly and had a great personality!
When I turned 16, my uncle bought me my first aquarium. I started with freshwater and naturally, I wanted to have a pet shark too – but a much smaller one. And so I started doing my research while my new aquarium went through the nitrogen cycle. This process allows the new aquarium to establish a healthy population of good bacteria so that it is inhabitable for fish and invertebrates.
While researching I came across several species that were referred to as “sharks”. Although it was pretty obvious that they were not “true’ sharks, they looked really cool, got along with a number of other different species and they had great personalities! So for me just starting out, they were perfect!
I kept several different species of freshwater sharks while I started to research saltwater sharks. Eventually that hobby would lead me to caring for, rescuing, rehabilitating and re-homing over 100 sharks with my good friend Matt Heyde as a young adult. You can learn more about that here: Shark Rescue Rehabilitation and Re-Home Project
In this article, we are going to take a look at the different species of “freshwater sharks”. The first species that we are going to take a look at is the Bull Shark.
During mating season the Bull Shark goes into brackish or even freshwater areas to breed and deliver their pups. This is the only species of shark that is able to do this to my knowledge. They cannot spend long period of time in freshwater though. It’s worth mentioning because this is the only species of shark that has been found in freshwater and that resembles the look of a “true” shark. The species that we are going to talk about next are true freshwater or brackish “sharks”.
Although they are named “sharks” there are actually small carp fish and catfish. Let’s take a look at the first species.
Bala Shark (Balantiocheilos melanopterus)
This shark goers by a few other common names such as the Tricolor Shark, Tricolor Shark Minnow, Silver Shark or Shark Minnow. This species should be kept in groups of 2 or more in the aquarium. They get to be 12 inches when full grown, so this needs to be considered before they are purchased.
They were given the category of “shark” because of their body shape, the way they swim and once they are larger, they can become semi-aggressive towards smaller fish in their aquarium.
In the wild, these sharks are found in Thailand, Indonesia and Malaysia. They were deemed an endangered species 1996. There has not been an update on their status since then. They are being bred in captivity so it is possible to help bring their numbers back in the wild if needed thanks to the aquarium hobby.
Colombian Shark (Ariopsis seemanni)
One of my personal favorites, this species is also referred to as the Tete Sea Catfish. Native to the rivers and estuaries in Central and South America, this species is unique in that it can live in both freshwater and saltwater during different times of their life. I was not told when I kept them that they needed to be slowly acclimated to a full saltwater tank once they became adults. I figured it out later on, so it’s important to mention. Also, there are varying opinions on how to acclimate them, when to and what the approximate salinity should be in order for them to thrive.
Like the Bala Shark, once this species gets large, it can become aggressive towards smaller fish. Like the Cichlids, the female Colombian Shark lays eggs and the male incubates them in his mouth in order to protect them.
They can grow to a minimum of 20 inches in length once full grown if they are properly taken care of. They are very active and need a lot of room to swim. Aside from their size, they are not easy to care for due to the venomous spine on their dorsal fins. So if you do decide to keep one as a pet, you need to be very careful when performing maintenance on their aquarium.
Red-Tail Shark (Epalzeorhynchos bicolor)
Also known as the Red-Tailed Black Shark and Redtail Shark Minnow, this species in the wild is critically endangered. They are regularly bred and available in the aquarium hobby. With their cool appearance and great personalities this was another one of my favorite freshwater sharks to keep as a teenager. They reach a maximum size of 6″ and they can live up to 5 to 6 years.
Native to Thailand, this fish is actually a carp fish and unfortunately due to poaching became pretty much extinct in the wild. If it was not for the aquarium hobby, this species would probably no longer exist.
In an aquarium, they like places to hide and they can be aggressive towards other species. If they are stressed, you will be able to tell by their tail color as it will fade. They are mostly bottom dwellers so it is recommended that if you do keep these fish that you do not keep them with any other bottom dwelling fish as they can become aggressive towards them. This includes algae eater, plecos, etc.
Albino Rainbow Shark (Epalzeorhynchos frenatus)
Also from Thailand, these sharks very closely resemble the Red-Tail Shark. Other common names for this species are Red Fin Sharks or Ruby Sharks. Their maximum length is 6 inches and they can live up to 5 to 8 years.
They are basically the albino version of the Red-Tail Shark. However, unlike the Red-Tail Shark, they are listed as Least Concern on the IUCN Red List.
Iridescent Shark (Pangasianodon hypophthalmus)
Often categorized as a “monster fish” this catfish can grow up to 3 feet and 3 inches in length or larger. Found in the rivers of Southeast Asia, this shark has a unique coloration that is iridescent.
This has made it become a very popular fish in the freshwater aquarium hobby due to its uniqueness. It is pretty common to find them in an albino coloration as well.
They eat smaller fish once they become large enough to do so. This can create a very serious issue if they are introduced as an invasive species. Since they outgrow most home aquariums, either they should be avoided completely for aquarium hobby or only kept in very large ponds.
In 2015 an environmental group in Colombia confirmed that iridescent sharks had been found in one of the tributaries that feed into the Magdalena river. They were said to have been accidentally introduced from illegal farm fisheries in the area. The find has caused alarm amongst the scientific community and government officials, as the Magdalena river is home to over 200 native fish species, 35 of which are endangered. Due to their size once fully grown and the recommendation to keep them in schools, this fish can decimate populations if released into the wild in the wrong area. They will now need to handle that matter in a way that will likely not be in favor of the iridescent sharks in that area unfortunately.
So it’s best to leave these species be unless you are prepared to house them in a very large – dedicated habitat. Another reason for not creating a demand for them is that they are endangered in the wild. As mentioned above they are cultivated for food so hopefully there will be efforts to restore their native populations.
So to answer the question, technically, there are no “true” freshwater sharks. Let me know in the comments below which species is your favorite.