Complete Guide To The Red Tail Shark

We independently research our recommended products. We may receive commissions on purchases made from our links.

There are fish that are flashy and eye-catching, and the red tail shark is definitely one of them. It has amazing coloration, with the sharp contrast of a mostly velvet-black body matched to a bright red tail.

This brilliant display has made the red tail shark a centerpiece for many home aquariums, despite the troubles this fish can bring. Though its name suggests otherwise, the red tail shark is not closely related to sharks.

red tail shark tank size
By An Ta (Creative Commons Attribution-Share Alike 2.0 licence)

The breed is a member of the Cyprinidae family, making them more closely related to carp. The red tail shark is also called the red tailed black shark and the red fin shark.

Before owning this fish, what should you know? What are its care requirements or health risks? To ensure you’re well prepared, we’ve gathered all the information you need to responsibly enjoy this gorgeous pet.

The Red Tail Shark vs. the Rainbow Shark

The red tail shark is often mistaken for its cousin, the rainbow shark. Because they both have the same shape and similar coloration, it can be easy to confuse one for the other.

Here’s how to tell them apart.

  • Both species have red colorations, but the rainbow shark has red coloration on all of its fins. The red tail shark only has a red tail, with the rest of its fins colored black.
  • The red tail shark will always have a black body. The rainbow shark also has a black body, but it’s more iridescent than the velvet-black of the red tail shark. The rainbow also has an albino variety, with a white body.
  • Both the red tail shark and the rainbow shark come from rivers, but that doesn’t mean they prefer the same water flow. The rainbow shark will prefer a moderate water flow, as they come from slower-moving rivers and streams.
  • Both red tail and rainbow sharks eat algae, but the rainbow shark is more reliable as a clean-up fish. Rainbow sharks are bottom feeders, which will eat algae both faster and in larger quantities than the red tail shark.
  • Because of their diet, the red tail and rainbow shark occupy different water levels. The red tail shark often inhabits the middle water level, with dips to the bottom level. The rainbow shark, on the other hand, prefers the bottom.
  • Because they are bottom feeders, the rainbow shark should be housed in an aquarium with a soft, sandy substrate. A rougher substrate, like the gravel and rocks the red tail prefers, will be harmful to the delicate body of the rainbow shark.

Red Tail Shark


The red tail shark comes from the rivers of Thailand and has been found as far as Bangkok. At present, there is only one known population of red tail sharks in the wild, in the Chao Phraya basin.

The red tail shark was considered extinct from 1996 to 2011; they are currently classified as critically endangered by the IUCN.

While the endangered status of the red tail shark can be credited to the aquarium trade, there is more evidence that environmental damage is responsible. A large number of dam construction and swamp drainage took place in the 70s, putting a strain on red tail shark’s habitats.

At present, the breeding of red tail sharks only occurs in captivity. Red-tailed sharks are bred in Thailand’s fish farms; this is where the supply for aquarium trade comes in.

red tail shark
By Astellar87 (Creative Commons Attribution-Share Alike 4.0 licence)

Size and Growth

The usual red tail shark size is about six inches for fully-grown adults. However, they can grow to larger sizes, as much as seven to eight inches in length.

Red tail sharks often live around five to six years in an aquarium. Of course, like with most fish, they can live longer with exceptional care. Some have been reported to live up to ten years or even longer.

Red Tail Shark Food

What do red tail sharks eat? The answer is: pretty much anything.

The red tail shark won’t give you trouble when it comes to its diet.

Meat and Veggies

They are omnivorous scavengers, meaning they will eat both meat and plant matter, including that which has fallen to the bottom of the tank.

Despite this, however, it’s still important to provide them high-quality fish food to maintain their health.

Varied and Clean Diet

Because they’re omnivores, it’s also wise to keep their diet varied. In the wild, red tail sharks primarily feed on plant matter, alongside worms, small insects, and crustaceans.

For home aquariums, their main diet consists of plant and vegetable matter. Good feeding choices include blanched zucchini medallions, cucumber medallions, and shelled peas.

High-quality, plant-based flakes or pellets can be substituted for typical flakes or pellets. If you’re using fresh vegetables, remember to wash them thoroughly and clean out all uneaten food immediately after feeding.

Don’t Overdo the Meat

The red tail shark’s diet should also be supplemented with meat. Frozen foods, like brine shrimp, blood worms, and frozen daphnia, make for great treats.

However, the red tail shark should always be fed more vegetables than meat.

what do red tail sharks eat

Is Algae Enough?

This breed is often marketed as an algae eater. However, they do not eat as much algae as other species and don’t make an effective cleaning fish.

Even still, be sure to provide algae for your red tail sharks. Ensuring your tank is brightly lit will encourage algae growth.

How Often Should You Feed a Red Tail Shark?

The red tail shark tends to supplement their diet beyond feeding times, such as with algae growing on an aquarium’s rocks and with uneaten food.

As a rule of thumb, the red tail shark should be fed every other day. This schedule is an excellent way to guarantee that they aren’t overfed, while also ensuring uneaten food doesn’t rot in the water.

Here’s a video explaining more on red tail sharks.

Red Tail Shark Care

Tank Set-Up

The red tail shark is territorial and aggressive, and this trait should be kept in mind when establishing their aquarium. While they will not actively harm fish, they tend to chase other fish, causing a great deal of stress.

Other than their aggressiveness, there are no special conditions that you need to keep in mind.

Water Requirements

The ideal temperature for the red tail shark is around 72 to 70 degrees Fahrenheit. Water pH should be about 6 to 8, with water hardness from 5 to 15 dH.

Because the red tail shark originally came from rivers, water flow should be fast to recreate the quick pace of rivers.

The tank’s substrate should also recreate a riverbed; gravel or large rocks make an excellent substrate for the red tail shark. When laying out gravel, try to use at least a ¼-inch, as the breed may try to eat smaller-sized gravel.

Tank Size

Because of the red tail shark’s aggressiveness, the size of their tank becomes even more critical. The more room they have to swim around, the less they will want to chase and stress out other fish.

A proper red tail shark tank size will be at least 53 gallons for one fish. Multiple red tail sharks will require a larger tank, so be sure to allocate at least one meter in tank length per shark.


Other than a large tank, another way of mitigating the aggressiveness of the red tail shark is through tank decorations. This breed should be provided with ample hiding spaces, like caves and rocks.

red fin shark

Because they’re scavengers, they will enjoy scooping up food in between nooks and crannies. Caves and hiding places will also be an excellent way to scope out a territory for the red tail shark.

Those with their own cave or hiding spot will be less likely to stress out other fish, provided they stay out of the shark’s territory.

While the red tail shark is aggressive to other fish, they will not harm plants. Tall plants can also break up their line of sight and give less incentive for them to chase other fish in the aquarium.

Red Tail Shark Tankmates

Red tail sharks may be marketed as a community fish, but their aggressiveness makes them a less-than-ideal tank companion. However, there is still a chance for red tail sharks to make friends in aquarium tanks.

The ideal tankmates are small and fast fish species. The most common tankmates are tetras, including the glowlight, emperor, rummy nose, cardinal, and neon tetra.

Characin and carp species are excellent tankmates, as they are fast and occupy different water levels. Other ideal species include:

On the other hand, bottom-dwelling species, like cichlids and catfish, are not suitable for the red tailed shark. Since they’re scavengers, they will be protective of the bottom of the tank, as this is where they find most of their food.

Docile and peaceful fish will also cave under the presence of the red tail shark.

Watch Out for Tankmates’ Appearance

Fish that look similar to the red tail shark should also be avoided. Similar ‘shark’ species, like the rainbow shark, will not make ideal tankmates; the same thing goes for species with a similar shape and silhouette, like the red-line torpedo barbs.

Red tail sharks have also been known to attack fish that have red coloration. While they may be a fast species that occupy different water levels, any red coloration should be avoided when choosing tankmates.

Of course, other red tail sharks should be avoided, especially if you do not have the tank space for them.

When putting a red tail shark in a community aquarium, it may help to add the red tail shark last. In this way, there is less chance of the shark interpreting other tankmates as encroaching on their territory.

Of course, one red tail shark will be different from another. Some sharks may be more aggressive; some may do well in a community tank.

If you believe that your shark can do well in a community tank, it doesn’t hurt to try. Just remember to keep a close eye on them, and move them out of a tank before they stress out or harm a tankmate.

Here’s a video with more information on red tail shark tankmates.

Breeding Red Tail Sharks

There is no physical difference that can be used to determine the sex of red tail sharks. The only obvious difference will be when the female is pregnant and her abdomen swells.

In the wild, red tail sharks breed in rocky caves. However, as they are critically endangered, their breeding is facilitated at fish farms in Thailand.

It’s wise to breed fish in a tank separate from the home aquarium, but this is especially true for the red tail sharks. This breed is very aggressive toward each other; two red tail sharks in a community tank will likely harm other fish.

Should you want to breed red tail sharks, always do it in a tank that houses only the two adults.

Shopping for a Red Tail Shark

The red tail shark is a popular fish for aquarium owners, which means that it shouldn’t be hard to find one in pet stores. However, these stores are often ill-equipped to house such a large and aggressive species.

When shopping for a red tail shark, it’s vital to ensure that they are healthy. A healthy fish should have a bright color, swim actively, and have a body in good condition.

Make sure to avoid fish that are sickly. Avoid fish that are pale, discolored, and have a hard time breathing. If you see frayed fins, bones sticking out, and visible parasites, this means that the fish is sick and needs medical attention.

Also be sure to note the condition of their tank. Bad water quality and dead or diseased fish in the tank means that these fish are kept in terrible conditions. Should you buy a fish from this tank, chances are, they will be sick as well.

red tailed black shark
By Adityamadhav83 (Creative Commons Attribution-Share Alike 3.0 licence)


The red tail shark has a reputation for being a trouble-maker, but their aggressiveness can be mitigated with the right aquarium set-up.

By providing enough space and the right decorations, this breed can be the perfect, eye-catching addition your tank needs.

Do you have experience with red tail shark?

Leave a Comment