10 Fearsome Freshwater Sharks

When most people hear the word “shark,” they immediately conjure up an image of the iconic character from one of the Jaws movies. A sleek, torpedo-shaped body, the high triangular dorsal fin, and a mouth chock-full of serrated teeth.

There are six species of sharks that venture into freshwater: the bull shark and five species of river shark from the Glyphis genus.

However, none of them make it into the aquarium trade! The tank size requirements defy an average aquarist’s capabilities.

Instead, when someone refers to their freshwater shark, they mean one of the dozens of Cyprinids or Catfish that share a passing resemblance to that shark silhouette.

They have pointed dorsal fins, forked tails, and (often) grumpy personalities.

Freshwater shark species hale from Southeast Asia, China, Africa, and South America.

However, your shark will probably arrive from a commercial fish farm.

Rarely do sharks come from the wild anymore. For good reasons – many are almost extinct in their natural habitats!

Debunking the Shark Image

No one quite knows where the “shark” label came from.

Some species share a few characteristics with the bigger marine sharks at some point in their lives. With others, you may need to squint to see the resemblance.

One thing all aquarists agree on is the massive size these freshwater fish attain.

While beginners might find the colors and shapes of juveniles attractive, they’re often unprepared for the final adult length of their new shark acquisition. Careful research of your species is crucial.

With a few exceptions, freshwater sharks have aggressive temperaments. This parallels with the shark stereotype, and it might contribute to the “shark” appellation.

Smaller fish often become unwitting snacks in community tanks.

Freshwater Sharks for Aquarium

With few exceptions, freshwater sharks require MAMMOTH aquariums!

Even a single fish needs hundreds of gallons/liters worth of swimming space to stay active and healthy.

The average beginning aquarist doesn’t have that kind of tank at their disposal.

So before you jump aboard the shark trend, make sure you’re prepared to handle the extra expense and size needs.

Nothing’s cooler than boasting you keep sharks, but those bragging rights come with a lot of responsibility.

Red-tail sharks catch and hold the eye.

The vivid red fins stand out against the midnight black body, and coloration persists into adulthood.

The very tip of the prominent dorsal fin holds a small white spot.

While popular among freshwater shark enthusiasts, red-tails have a tragic past.

Development along the Chao Phraya River in Thailand, where red-tails come from, has led to the near-extinction of the species. Aquarists rely on captive breeding for their acquisitions.

Red-tails take their shark name to new levels.

You can only keep ONE red tail shark in a tank. They’ll attack each other, other sharks, and catfish without hesitation.

While they don’t have sharp teeth, they’ll nip at flowing fins or the flanks of slow-moving fish.

Rainbow sharks share a similar appearance to red tail sharks. They have a dark body with pink or red fins, though they don’t achieve the same black coloration as red tails.

Selective breeding has produced some albino varieties, as well.

Rainbow sharks take their shark label seriously, bullying and harassing peaceful and smaller tank mates.

Your best bet is to pair them with larger fish that can hold their own against rough treatment. If you like calmer species, keep them in a separate aquarium.

Rainbows DON’T tolerate other sharks infringing on their territory.

While red-tails can hold their own, you’re better off avoiding other sharks. The battles over territory aren’t worth the injuries that will result.

Most people see juvenile iridescent sharks in pet stores and jump at the chance to include freshwater sharks in their aquarium.

The purple-black iridescence, flecked with tones of white, looks intriguing, and the fish generally don’t break the bank.

Unfortunately, iridescent sharks don’t belong in the average home aquarium.

Adults reach a staggering 36 inches (91cm) when full-grown!

Plus, this fish wants to swim in schools. That means you need to provide TONS of space.

Iridescent sharks share ancestry with the Mekong giant catfish (Pangasionodon gigas). They reach lengths of 10 feet (3m), holding the title of one of the longest freshwater fish in the world.

No wonder iridescents tend to hang out in professional installations.

If you have your heart set on a freshwater shark but don’t want to invest in a gigantic aquarium, roseline sharks fit the bill. Best of all, they only reach a length of 4 inches (10cm) as adults!

These colorful fish sport blue and red stripes on the sides and yellow patterns along their tails.

That said, roselines still need schools to stay happy and healthy. You’ll want at least six in the group.

When you hit the store, make sure you get captive-bred.

The roseline shark is endangered in their native waters of India, and you don’t want to contribute to the dwindling numbers.

Roseline sharks rank as the easiest freshwater shark to manage.

So if you’re getting your feet wet, they’re your best bet as a starter species. Their water conditions aren’t demanding, and they aren’t picky when it comes to diet.

The black sharkminnow may not have much in the way of flashy colors, but their purplish-black color and flowing fins make for a striking appearance.

Selective breeding has also produced an albino version if you want something more unique.

When it comes to size, the sharkminnows claim a big bite of the prize.

Topping out around 24 inches (61cm) and 25 pounds (11kg), your tank needs plenty of room for these sharks to roam.

Tank mates better be fast enough or of comparable size to compete!

If you opt for a black sharkminnow, make sure it’s the LAST fish you add to the aquarium.

If you try introducing newcomers after your shark, it’ll become hyper-aggressive and attack the new fish infringing on its territory.

Bala sharks make frequent appearances in pet stores. The shining scales with contrasting black borders make them attractive additions to many aquarists.

Unfortunately, people don’t realize those little juveniles will quickly grow to over 12 inches (30cm) long!

Despite the “shark” title in their name, Balas have a skittish nature.

This goes double if you only bring one home. Bala sharks are shoaling fish, and without a school for defense, they’ll launch themselves at the tank walls and lid in a panic.

To avoid such behaviors, you need several Balas. That means a tank of appropriate size.

Even with friends around, don’t be surprised to find your sharks testing the lid of the tank. Make sure you have a tight fit, so no one ends up on the floor!

Colombian sharks have a silvery blue coloring that many aquarists find appealing.

They’re a predatory species of catfish, selecting a variety of foods for their diets. That includes tank mates small enough to fit in their mouths, so be careful.

Colombians need schools to feel safe and prevent skittish jumping at the lid of the tank.

As with other catfish, they DO have venomous spines along the dorsal and pectoral fins.

Be careful when handling them. If you get a puncture, run your hand under water as hot as you can stand.

While not the most challenging freshwater shark to care for, Colombians throw aquarists a twist.

As adults, they require a transition to brackish and then saltwater. Which means you need THREE large tanks prepped and ready to go!

People that select Chinese High-Fins gravitate toward the juveniles.

Youngsters have attractive bands of brown and black on a peach background with that recognizable sail dorsal fin arching over the back. Adults? Not so much.

Unlike most fish, Chinese High-Fins gradually lose their color over the first two years.

Adults switch over to drab coloring, and the sucker-type mouth becomes more prominent. They look similar to the Chinese Algae Eater.

In China, this freshwater shark falls on the endangered list.

Aquarists procure the cold-water species from captive-bred ponds.

That aversion to warm temperatures contributes to the decline of the species in the wild. (Climate change is NOT a good thing!)

Harlequin sharks have a dappled patterning that mimics sunlight and shadows passing through tangles of weeds.

As this species prefers to hang out along the bottom, the coloring makes perfect sense. It also adds a nice touch of color to your aquarium.

Harlequins are territorial. You need to make sure you provide a cave or grotto to prevent them from claiming the entire bottom of the tank as their own.

You also want to make sure they’re the LAST addition to a tank to cut down on bullying and harassment.

The stereotypical shark image applies with harlequins when it comes to home turf.

DON’T add other bottom-dwellers to your aquarium unless you want to cause trouble. Harlequin sharks WILL attack more defenseless catfish without a second thought.

Silver Apollo sharks sport a sleek torpedo shape with shining silver scales.

That shape helps them cut through the middle and top of the water column. You’ll want to make sure you have plenty of water current to keep them happy.

While you might get away with keeping a single silver Apollo in a smaller tank, they ARE schooling fish. You need a minimum of six.

And make sure the lid’s on tight because silver Apollos have phenomenal jumping abilities!

Read the label carefully when you buy your sharks. The long-finned Apollo shark (Luciosoma spilopleura) looks VERY similar.

However, long-finned are solitary and aggressive. If you introduce it to the group, it will kill the others.

Freshwater Shark Tank Setup

Freshwater sharks share another common characteristic with their marine “cousins”: a tolerance for varying water conditions.

Most species prefer warmer waters, but there are exceptions.

Be sure to research your shark’s needs before you bring it home.

Species	Temperature	pH	Hardness	Nitrites	Ammonia	Nitrates
Bala Shark	77-80°F (25-26.6°C)	6.5-8.0	10-13dH	0ppm	0ppm	0ppm
Black Sharkminnow	72-82°F (22.2-27.7°C)	6.5-7.5	2-10dH	0ppm	0ppm	0ppm
Chinese High-Fin Banded Shark	55-75°F (12.7-23.8°C)	6.8-7.5	4-20dH	0ppm	0ppm	0ppm
Colombian Shark	75-80°F (23.8-26.6°C)	7.0-8.0	10-12dH	0ppm	0ppm	0ppm
Harlequin Shark	72-81°F (22.2-27.2°C)	6.0-7.5	3-15dH	0ppm	0ppm	0ppm
Iridescent Shark	72-79°F (22.2-26.1°C)	6.5-7.5	2-20dH	0ppm	0ppm	0ppm
Rainbow Shark	72-79°F (22.2-26.1°C)	6.5-7.5	5-11dH	0ppm	0ppm	0ppm
Red Tail Shark	72-79°F (22.2 -26.1°C)	6.5-7.5	10-15dH	0ppm	0ppm	0ppm
Roseline Shark	60-77°F (15.5 -25°C)	6.6-7.8	5-25dH	0ppm	0ppm	0ppm
Silver Apollo Shark	72-78°F (22.2-25.5°C)	6.0-6.5	2-20dH	0ppm	0ppm	0ppm

While these species have significant tolerances for temperature and pH, they require pristine water conditions.

NEVER introduce a freshwater shark into an aquarium that you’re struggling to stabilize.

This is one of the reasons beginners should avoid freshwater sharks.

While freshwater sharks may tolerate an occasional spike in ammonia or nitrites, the window is narrow. The amount of variance is even shorter.

Your ammonia can’t go higher than 0.02 ppm, and your nitrites no higher than 0.2 ppm.

Diet: Jaws?

While freshwater sharks may snatch up a tank mate without hesitation, these species are omnivores.

Many of the catfish in the group have sucker-type mouths designed to rasp algae from rocks and driftwood in the tank. (Your fingers are safe)

Even the toothy varieties enjoy some plant-life in their diet.

Rotating between frozen and live foods improves their color and growth.

A selection of different foods keeps these sharks happy:

• Algae rounds
• Bottom feeder tablets
• Flake foods
• Shrimp pellets

When is a Shark Not a Shark?

Freshwater sharks might not pose a risk to fingers or toes that dip into the aquarium.

However, their unique appearance still adds character to your tank. And with the extra demands of their care, you earn respect from fellow aquarists whenever you mention owning freshwater shark species.

Have you entered the freshwater shark craze?

Which species is your favorite? Let us know by commenting here!