If you’ve ever tried to create a robust ecosystem within a freshwater aquarium, you know that there is one role that can be exceptionally hard to fill: the role of the apex predator. What you might know is that there is a group of fish that can fill it; they are known as freshwater sharks.
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Freshwater Aquarium “Sharks” are Not Actual Sharks
Before we discuss our favorite freshwater sharks, it is important to make one thing clear: freshwater sharks are not actual sharks.
Sharks are elasmobranch fish that belong to the superorder Selachimorpha. Sharks are primarily marine animals (there are only five known freshwater species) that are extremely difficult to keep in captivity due to their size, appetite, and migratory nature.
Freshwater sharks, on the other hand, are scientifically not sharks at all.
Freshwater sharks are a group of fish that have been nicknamed “sharks” because their physical appearances or personalities are similar to their marine namesakes. Most freshwater aquarium sharks are members of the Pangasiidae family (nicknamed the shark catfish family) or the Cyprinidae family.
Freshwater sharks typically have torpedo-shaped bodies, pointed dorsal fins, and forked tails. Nearly all of the freshwater sharks eat meat, and many are aggressive and/or territorial.
But don’t let this distinction dissuade you- these fish were aptly named. Freshwater sharks will bring the deadly confidence and cool grace of their marine counterparts to any aquarium they enter.
Best Sharks for Freshwater Aquariums
1. Roseline Torpedo Shark
- Experience Level: High Beginner
- Temperament: Peaceful
- Maximum Size: 5-6″
- Minimum Tank Size: 75-125 gallons
- Lifespan: 5+ years
- Diet: Omnivore
The Roseline Torpedo Shark, also known as the Denison’s Barb and the Red-Lined Torpedo Barb, is the only shark on this list that could be considered beginner-friendly. As the name suggests, they are white and yellow fish with bold black and red lines running the length of their bodies.
Roseline Torpedo Sharks are schooling fish that are relatively peaceful as long as they are kept in a school of five or more individuals. Though they are not aggressive, they should be housed with other fast-swimming species, as their hyper personalities can stress out slower fish.
In addition to their personalities, these fish are great for beginners because they are very undemanding. They will thrive in a wide range of water qualities and temperatures and will eat almost anything.
2. Bala Shark
- Experience Level: Intermediate
- Temperament: Peaceful
- Maximum Size: 15-20″
- Minimum Tank Size: 150-200 gallons (3 or more fish)
- Lifespan: 10+ years
- Diet: Omnivore
The Bala Shark, also known as the Tricolor Shark, the Tricolor Shark Minnow, the Shark Minnow, and the Silver Shark, is a silver fish with black lined fins.
Bala Sharks are schooling fish that are happiest in schools of 3-6 individuals. They are a peaceful species that live in the middle water column of the tank and should be housed with other peaceful semi-large fish.
Bala Sharks are a recommended freshwater aquarium shark species to start with because they are hardy fish and eager eaters; they will pounce on any food that enters the tank. However, because they are large fish, they require much larger tanks than typical beginner fish.
The biggest challenge with Bala Sharks is creating a diverse tank ecosystem. Bala Sharks are curious, adventurous fish that need plenty of decorations and plants to keep them entertained.
3. Siamese Algae Eater
- Experience Level: Beginner
- Temperament: Peaceful
- Maximum Size: 6″
- Minimum Tank Size: 20 gallons
- Lifespan: 10 years
- Diet: Omnivore
In our opinion, the physical traits of the juvenile Siamese Algae Eater are the farthest from the stereotypical shark body of any species on this list. However, as they grow, their strong dorsal fins and forked tails do bring to mind the melody of Jaws.
If you’re looking to add a freshwater shark to your established freshwater aquarium without a lot of additional costs or time commitment, this is the shark for you. Siamese Algae Easters are inexpensive, peaceful sharks that will get along with almost any tankmates.
Siamese Algae Eaters can be housed singly or in groups. However, avoid pairings of 2-3 to minimize territorial disputes. As a rule of thumb, you should add at least 15 additional gallons of water for every Siamese Algae Eater you add.
The best part about adding Siamese Algae Eaters to your freshwater aquarium should be clear based on their name- they eat algae!
Siamese algae eaters are some of the best algae eaters you can find for a freshwater tank and can be very beneficial for overall tank maintenance.
4. Rainbow Shark
- Experience Level: Intermediate
- Temperament: Semi-Aggressive
- Maximum Size: 6″
- Minimum Tank Size: 55 gallons
- Lifespan: 6-10 years
- Diet: Omnivore
Rainbow Sharks, aka Whitetail Sharks, Ruby Sharks, White Fin Sharks, and Redfin Sharks, are another of the small shark species. They only reach 6″ long as adults, and therefore can thrive in a much smaller tank (55 gallons) than most of the species on this list.
However, while their name is bright and cheery, their personalities are not. The biggest challenge with Rainbow Sharks is finding them tankmates that they can tolerate.
As these bottom-dwellers mature, they become increasingly aggressive and territorial. Therefore, Rainbow Sharks mustn’t be housed with other bottom-dwellers or with peaceful fish, as they will mercilessly bully them.
Rainbow Sharks are also aggressive towards each other, as well as any other brightly-colored species. Therefore, they are best housed singly with species that won’t steal their spotlight.
There are a number of things you can do to decrease your Rainbow Shark’s aggressive tendencies:
- Provide plenty of plant life and rock formations in your tank. With a cave or grotto to call their own, Rainbow Sharks will defend their area, thereby leaving the rest of the tank for your other species.
- Introduce them last in an established community tank so that they can’t bully new fish as they are introduced.
- Pair them with fish that occupy the middle and upper water columns.
Once you establish tankmates that can coexist with your Rainbow Shark, the Rainbow Shark can be the perfect combination of danger and beauty to add to your freshwater aquarium.
5. Red-Tailed Black Shark
- Experience Level: Intermediate
- Temperament: Semi-Aggressive
- Maximum Size: 6″
- Minimum Tank Size: 55 gallons
- Lifespan: 7-15 years
- Diet: Omnivore
The Red-Tailed Black Shark, also known as the Red-Tailed Labeo, Fire Tail, and Labeo Bicolor Shark, is by far the most striking freshwater aquarium shark on this list. With its jet black to navy blue body and vibrant red tail, it is sure to steal the spotlight of any tank it’s put in.
The Red-Tailed Black Shark is similar to the Rainbow Shark in both habitat requirements and temperament. It is another small shark species (reaching only 6″ in length at adulthood) that gets progressively more aggressive and territorial as it matures.
Red-Tailed Black Sharks should be housed singly in a tank that does not have bottom-dwelling fish or fish that are similar in shape or coloration. They do best with fish species that schooler in the upper water columns of the tank, such as tetras or barbs.
The Red-Tailed Black Shark will thrive in a tank with a diverse ecosystem. As a juvenile, Red-Tailed Black Sharks are timid and will need plenty of plants and caves to hide in. As an adult, having caves and plants will decrease the aggression of the Red-Tailed Black Shark and the stress levels of its tankmates.
Red-Tailed Black sharks are voracious omnivores that will fill their time between meals eating algae and scavenging for food scraps. What they lack in manors, these beautiful sharks certainly make up for in cleanliness and beauty.
6. Harlequin Shark
- Experience Level: Intermediate
- Temperament: Semi-Aggressive
- Maximum Size: 6.5″
- Minimum Tank Size: 55 gallons
- Lifespan: 5-8 years
- Diet: Omnivore
The Harlequin Shark is the most unusual of all the freshwater shark species. It is a vibrant orange fish with whimsical black patterns across its fins and body. Though its colors fade with age, the Harlequin Shark will remain a bright addition to your tank.
Harlequin Sharks are large, quick-swimming fish with even quicker tempers. They are solitary bottom-dwellers that will be territorial against other catfish and other bottom-dwellers. Therefore, they are best housed singly with fish species that live in the middle and upper water columns.
Harlequin Sharks are found in river systems, so they prefer tanks with significant water flow. They are grazers so that they will be happiest in tanks with plenty of live plants and algae-covered substrates.
If you are looking for a unique bottom-dwelling fish to round out your community, look no further than the Harlequin Shark.
7. Silver Apollo Shark
Image Source: ©Nonn Panitvong/Siamensis.org
- Experience Level: Intermediate
- Temperament: Peaceful
- Maximum Size: 6-9″
- Minimum Tank Size: 75 gallons for a single specimen
- Lifespan: 14 years
- Diet: Omnivore
The name “Silver Apollo Shark” actually refers to two different fish species: Luciosoma pellegrini and Luciosoma setigerum. The two species are nearly identical in appearance, care requirements, and disposition; as such, it doesn’t really matter which species you choose.
Silver Apollo Sharks are schooling fish that prefer to be housed in groups of six or more. When housed in groups of four or less, the fish tend to stray towards hierarchical infighting.
Silver Apollo Sharks are non-aggressive fish and are well-suited for most tank environments. However, they are predators, so it’s important to make sure their tankmates aren’t too small, or they will quickly become the Silver Apollo Shark’s next meal.
The biggest challenge with Silver Apollo Sharks is their sensitivity to environmental changes. They are instantly stressed by changes to pH levels, ammonia, and nitrites. Therefore, your aquarium will require a strong filter and weekly 25% water changes if you want to keep them healthy.
One word of warning: When purchasing a Silver Apollo Shark, double-check the species name! The Long-Finned Apollo Shark (Luciosoma spilopleura) is frequently mislabeled as the Silver Apollo Shark because they are nearly identical when juveniles. However, Long-Finned Apollo Sharks will grow up to 12″ long and are much more aggressive.
8. Black Shark Minnow
- Experience Level: Expert
- Temperament: Semi-Aggressive
- Maximum Size: 35″
- Minimum Tank Size: 200+ gallons for adults
- Lifespan: 10 years
- Diet: Omnivore
Black Shark Minnows, also known as Black Labeos, are one of the most stereotypical sharks in the group. Their large size (they are over 25-pounds as adults) and aggressive behavior, combined with their inky black scales and dramatic fins, make them the natural apex predator of the tank.
Though juvenile Black Shark Minnows can be housed in a community aquarium fairly easily, adult Black Shark Minnows will prey on smaller fish and bully other bottom-dwellers. Adults are best-suited for large pond settings with goldfish, koi, barb, or danio tank mates.
If you do add them to your tank, make sure Black Shark Minnows are added last to avoid unnecessary bullying. Black Shark Minnows are omnivores that require a diet of both meaty foods and vegetables.
If you’re looking for a fish that looks and acts like a marine shark, you cannot do better than the Black Shark Minnow for your freshwater aquarium. However, their added size brings added challenges; make sure you’re up to the task before you buy!
9. Iridescent Shark Catfish
- Experience Level: Expert
- Temperament: Peaceful
- Maximum Size: 50″
- Minimum Tank Size: 400 gallons for single specimen, 1500+ gallons for a school
- Lifespan: 15-20 years
- Diet: Omnivore (juvenile), Herbivore (adults)
Iridescent Shark Catfish, also known as Sutchi Catfish, are sold in most pet stores as small, purple, and black fish with adorable whiskers. However, they don’t stay small and cute for long. As one of the largest shark species, Iridescent Shark Catfish will eventually reach 50″ in length, far surpassing the bounds of typical home aquarium systems.
Unlike other large sharks, Iridescent Shark Catfish are schooling fish that live fairly active lifestyles. They are relatively non-aggressive but will eat anything they can fit in their mouths without judgment, especially as they’re growing. Therefore, they are best housed with other large fish or with bottom-dwellers who will stay out of their way.
The coolest thing about Iridescent Shark Catfish is that their diets change over time. As juveniles, they are voracious omnivores. However, once they reach adulthood, they slowly transition into herbivores. Therefore, as their caretaker, you will have to alter their diet as they grow.
Iridescent Shark Catfish are one of the most endangered species on this list. To help protect the species, please buy captivity-bred individuals.
10. Chinese High-fin Banded Shark
- Experience Level: Expert
- Temperament: Peaceful
- Maximum Size: 50″
- Minimum Tank Size: 300 gallons
- Lifespan: 25+ years
- Diet: Omnivore
The high, arched back and sail-like dorsal fin of the Chinese High-fin Banded Shark gives it the most striking profile of any of the shark species. The juvenile is a beautiful peach color with dark brown to black bands running around its body.
However, as the juvenile quickly grows, it undergoes a “reverse-ugly-duckling” transformation; the fish loses its bright coloration and becomes a cigar-shaped brown fish with a strong, elongated dorsal fin. Be prepared for this change, so you don’t have buyer’s remorse.
Though not a tropical fish, the Chinese High-fin Banded Shark can easily adapt to waters up to 75oF. However, they are happiest in outdoor ponds and unheated aquariums that more closely mimic their cold-water environment.
Chinese High-Fin Banded Sharks are peaceful grazers that can be easily assimilated into tanks with fish of all sizes. They will laze along the bottom of the tank consuming algae, detritus, and any other organic matter than they can find.
As long as they are given plenty of space and plenty of food, these behemoths are relatively easy to care for and can be the perfect companion for any lifelong aquarist.
Care Tips for Freshwater Aquarium Sharks
Freshwater aquarium sharks can be a fantastic addition to a freshwater aquarium. However, they are also challenging fish that should not be purchased by the faint of heart. Before buying a freshwater aquarium shark, make sure you do the following things:
- Do Your Research: Depending on the species, freshwater sharks can be aggressive or carnivorous. Therefore, it’s extra important to ensure that you pick tankmates that won’t be bullied or eaten by your shark before you put it in your tank.
- Get a Long Tank: Most freshwater sharks are bottom-dwellers. Therefore, the size of the aquarium bed will likely be more important than the size of the aquarium as a whole. Make sure you get a long aquarium that fits your freshwater sharks’ tank size requirement.
- Provide Decent Filtration: Any time you add a large or carnivorous fish to your aquarium, the amount of waste produced in your tank is going to increase dramatically. Unless you want to spend your life making hourly water changes, make sure you get a filtration system that can keep up with your shark’s habits.
- Keep a Tight Lid at All Times: Strangely enough, though most freshwater sharks are bottom-dwellers, most are also jumpers. Unless you want to be on constant patrol for fish suicides, make sure you keep a tight lid on your tank.
- Provide a Soft Substrate: Though they have tough personalities, most freshwater sharks are still bottom-dwellers with sensitive bellies. Therefore, it’s important that you get a smooth or sandy substrate that they won’t harm themselves on.
- Provide a Robust Ecosystem: When you introduce a territorial species to a tank, it’s important that there are plenty of plants, rocks, and decorations in the tank to separate contenders. By providing a robust ecosystem, you ensure that your shark has an area to call their own and that your other fish have easy hideaways to run to when the bully is on the prowl.
- Add Your Shark Last: When creating a freshwater aquarium, it is always best practice to introduce your most aggressive species last. This way, they are not bullying other fish that are entering the tank and trying to acclimate. These sharks will typically be the apex in your tank; therefore, they should be added once all of your other inhabitants have been acclimated.
- Purchase Environmentally: Even more so than other freshwater aquarium species, freshwater aquarium sharks are frequently overfished and endangered. Therefore, when purchasing your shark, make sure you are receiving an individual that has been bred in captivity so that you are not harming wild populations.
Final Thoughts
Though freshwater aquarium sharks aren’t related to the sharks you see on Shark Week, they nonetheless seamlessly capture the silhouette and spirit of their marine counterparts. If you have the skill and gumption to raise freshwater aquarium sharks, it is worth taking the plunge. When placed in the right aquarium with the right tankmates, these incredible species will elevate both the aesthetic and atmosphere of any freshwater aquarium.
