Red Tail Shark: Size, Food, Tank Mates, Care…

Do you want to keep a shark in your aquarium?

The Red Tail Shark might be exactly what you are looking for.

This beautifully colored tropical fish is one of the smallest freshwater sharks around. Their size means they can can fit into a variety of medium to large aquariums. However, they certainly do not act as small as they are.

Red Tails are hot tempered fish (just like Convict Cichlids) and keeping them in a community requires some extra work and effort.

If you are thinking about keeping this fiery little freshwater shark then keep reading to learn everything you need to know…

Red Tail

Red Tail Shark Fish Overview

When most people think of sharks they think of the ferocious saltwater predators (like the Great White) from the class Chondrichthyes.

A Red Tail Shark (Epalzeorhynchos bicolor) is a freshwater shark that is very different from a marine shark – this is a bony fish and not a cartilaginous fish.

They are often referred to as the Red Tail Sharkminnow, Red Tail Black Shark, or the Red Tail Labeo.

Their popularity comes from their unique sharklike appearance and when kept in an aquarium you can except them to grow to 4-6 inches.

Although they are fine when kept alone, they have a reputation for being aggressive and bullying other fish. However, with the correct setup it is possible to keep them in a community tank (more on this later).

Expect to pay around $5-$8 for a single species from most retailers.

Key Facts:

  • Experience Required: Intermediate.
  • Nicknames: Red Tail Sharkminnow, Red Tail Labeo and Red Tail Black Shark.
  • Color Forms: Red and black.
  • Size: 4-6 inches.
  • Tank Size: Minimum 55+ gallon.
  • Tank Temperature: 72°F-80°F.

Epalzeorhynchos bicolor Close Up


  • Small and manageable size.
  • Affordable.
  • Good for pest control and algae cleaning.
  • Lives for a long time.

  • Aggressive to other fish.
  • Preys on most invertebrates.
  • Large tank needed if kept in a community.

Red Tail Shark Appearance

Red Tail Shark

The Red Tail Shark is very similar to another sharklike cyprinid, the Rainbow Shark. The difference is the color of their fins.

While all 6 of the Rainbow Shark’s fins are red, the Red Tail Shark is completely black with the exception of their red tail.

This feisty fish only grows up to 6 inches long and most only reach 5 inches.

They are shaped like a jet and have a streamlined body with a pointed snout which helps them power through high flow areas. If you look closely you will notice they have several barbels on their snout which are used to sense the movements of small prey in the substrate.

Similar to most other ray finned fish they have 6 different fins: The high, sloping dorsal fin and the bright red caudal fin are the first two that you will notice. In addition to that the fish has a pair of sail shaped pectoral fins followed by a single pelvic and anal fin.

You can only find them in one color form: red and black.

There are no additional color varieties for this species. You may have heard of an Albino Red Tail Shark or seen one for sale at an aquarium supplier, but this is actually an albino form of the Rainbow Shark.

The intensity of their color depends on the age. Juveniles fresh out of the fry stage are usually dingy grey with a deep orange caudal fin. As they grow old this color will darken to jet black and an extremely vivid red. However when they reach old age their color will fade to pale red and grey.

There are very little differences between the two genders, but you can tell a male from a female by taking a look at the abdomen. If your fish is built more like a straight line then it is male. If it has a rounded abdomen then it is female.

Habitat and Tank Conditions

Red Tail Shark Substrate

These fish are native to Chao Phraya River in Thailand.

They are very active fish that hardly ever stop moving. Red Tails love to ride the currents in high flow areas within the river. While they tend to remain close to the substrate they will often venture to other depths in the water columns too.

In the Chao Phraya River the water is heavily acidic, murky and full of decaying plants.

Let’s look at how to replicate this in your home aquarium.

Ideal Tank Set Up

Let’s start by looking at the water conditions.

The temperature should be kept between 72-80°F – it must remain consistent without any sudden drops or rises.

In their native environment you will find lots of decaying plants which helps to acidify the water column. You should mimic this in your tank by maintaining a slightly acidic pH range, between 6.5 and 7.5.

The water hardness should be between 5-12 dGH, and there should be a moderate to high flow. The tank will need a hood or a heavy lid to stop the fish from jumping out too.

For the substrate you can use medium sized gravel or small pebbles (light colored gravel will make the fish’s colors stand out). In a community setup you can divide the tank into partitions using larger rocks. Use large boulders, logs, or even plexiglass to give each fish or group of fish in your aquarium their own space. You can also use large rocks, caves, arches and logs for the shark to use as hiding places.

Your tank should be heavily planted too (especially towards the bottom levels). Large, shady plants are the key here. Amazon Sword plants and Water Wisteria have very large leaves that a secretive shark can use as a hiding place.

Depending on your tank’s size and the number of other fish in your tank you can use either an internal or an external filter that generates a fast moving current.

Red Tail Sharks appreciates well oxygenated water so it would not hurt to include a few air stones or an air pump. The light intensity should be low to moderate.

Tank Parameter Requirement
Minimum Tank Size 55 Gallons
Tank Type Freshwater Planted
Temperature 71-80°F
pH 6.5-7.5
Hardness 5-12 dGH
Flow Medium to Heavy
Substrate Medium sized gravel or pebbles

What Size Aquarium Do They Need?

It is a common misconception that these small fish can live in a small tank.

This is wrong.

A Red Tail Shark will need at least a 55 gallon fish tank.

If you want to keep them in a community then you should use at least a 100 gallon tank.

Red Tail Shark Tank Mates

Red Tail Shark Tank Mates

The Chao Phraya river basin is a very diverse habitat, so this fish naturally has lots of wild tank mates. These include freshwater flounder, Rasboras, small cyprinids and different catfish species.

Unfortunately though in an aquarium they do not suit community setups because of their territorial nature.

Red Tail Sharks are compatible with fast moving or schooling fish that inhabit only the middle and upper levels of your tank. In a very large tank you can also include a Bala Shark as this peaceful freshwater shark usually remains near the surface.

Barbs are another good choice because they move so fast and tend to travel in groups. Try the Tinfoil, Rosy, or Tiger Barb. Danios are known for being compatible too. Giant Danios and small schools of Zebra Danios are also good additions to this tank.

Some of the more robust Gouramis are also a good choice. Blue, Pearl and Paradise Gouramis are three of the best options.

While Tetras can be a bit risky to add due to their size and their timid behavior, it should be all right to include a large school of fast moving Neons or Glowlights.

You should avoid Rainbow Sharks and other similar sized Sharkminnows.

Cichlids and other aggressive species should also be avoided. Loaches, Catfish, and other slow moving bottom dwellers are out as well.

Do not add any invertebrates to your tank also as as your shark is likely to eat them.

Keeping Red Tail Sharks Together

Red Tails are on their worst behavior around their own kind or any similar species. You are better off not keeping them together at all.

However if you do decide to keep a few together then you should use at least a 100 gallon tank. Divide the tank into separate sections so each shark can have their own space.

First timers should never attempt to keep them in a group.

Red Tail Shark Care Guide

Red Tail Shark Swimming

This fish is best for keepers with at least some amount of fishkeeping experience.

Despite their reputation for being aggressive, with a good keeper and proper conditions they will be manageable.

The good news is they are extremely hardy and adapt very well to slowly shifting water parameters. They do not sudden rises and drops in temperature very well.

Streptococcus iniae is the most common disease with this fish.

The symptoms of this illness include poor balance, uncoordinated swimming, erratic behavior, and lethargy. An active fish behaving sluggishly is definitely a cause for concern.

If left untreated it can be fatal, however it can be treated with antibiotic medication. Keeping your tank clean is the best way to prevent any streptococcal infection.


There is very little that this scavenger will not eat. They can be kept as a both an algae cleaner and an exterminator.

This Red Tail Shark will eat more plants than meat.

Most of their diet is made up of greenery but they will also eat worms, zooplankton, and other small prey.

In an aquarium you should feed them a mixture of fish flakes and live prey in the aquarium. Fish flakes should be high in protein and supplemented with algae flakes. Live foods include all types of water fleas, adult and larval brine shrimp, small worms, and insect larvae. You can also feed it frozen, chopped up krill.

Algae is their favorite food though and they will find this growing on the rocks and substrate.

Homemade vegetables make the perfect treat for a fish that loves to eat greens. Zucchini, cucumbers, peas, and other green vegetables make tasty and healthy snacks for sharks.

These fish are active from dusk till dawn so that is when you should feed them.

They will only need once every 2 days as the rest of the time, they will find their own food in your tank.

Red Tail Shark In A Tank


You will usually find this fish hiding at the bottom levels of the aquarium. However when they are active, they enjoy exploring the middle and upper levels too.

This little shark is both timid and hot tempered.

They will spend most of their time hiding out in caves near the bottom of the tank.

Red Tails will only lashes out when another fish gets too close. They will chase the intruder down and follow them all through the tank! The shark does not bite or nip though and is unlikely to go after anything above the bottom levels. It does not prey on fish but it will eat small invertebrates.

Just remember that this fish does not get along with their own kind or similar species. A group of them will terrorize each other to death.

Breeding Red Tail Sharks

It is nearly impossible to breed this fish in a home aquarium.

All of the captive breeding of this fish is done on commercial outdoor fish farms using artificial means.

If you do want to breed these sharks at home then you will need a large heated pond with lots of vegetation and plants.

You must keep a group of at least 5 sharks, with 4 females to one male. If you keep too more than a single male then your fish will fight for dominance and could end up killing each other.

Once one of your females selects the male as her partner, you will notice the male swimming rings around her. He will isolate himself from the rest of the group and spend all of his time with the female.

This breeding pair should be fed a high protein diet.

Copulation is rarely visible and occurs very quickly.

However, a pregnant female has a visibly rounder abdomen and will carry up to 40 eggs at a time.

Spawning occurs in caves and rocky crevices near the bottom of the pond and the male will defend the eggs by chasing away any intruders.

It will take around 3 days for the eggs to hatch and a further 2 days until the larvae lose their yolk sacs. At this stage of life, the fry will be pale and transparent in color.

You can feed them infusoria and larval prey.

Your juvenile fish will take a total of 2 months to reach adulthood, after which time they can be placed in their own setup.

History and First Sighting

Epalzeorhynchos bicolor

The Red Tail Shark was first described by Mr Smith in 1931 and they were discovered in Thailand’s Chao Phraya River.

Initially they were classified under the Labeo genus of cyprinids. However by 1997 they had been moved into their own genus along with 3 other species.

At the time of their discovery the Chao Phraya River was full of Red Tail Sharks. However exports for the aquarium trade began in the early 1990s, and by 1996 the species was considered extinct in the wild.

Fortunately wild populations were discovered in 2011 and 2014, reclassifying the species as critically endangered. The current status of these populations is unknown.

Nearly all Red Tails available to buy today have been breed in captivity which allows the few left in the wild to potentially recover their populations.

The current captive populations of Red Tail Sharks are bred only on ornamental fish farms.

Species Summary Table

Red Tail Shark
Other Common Names: Red Tail Sharkminnow, Red Tail Labeo and Red Tail Black Shark
Scientific Name: Epalzeorhynchos bicolor
Family Name: Cyprinidae
Distribution: Thailand
Size: 4-6 inches
Color: Black with red tail
Care Level: Intermediate
Temperament: Aggressive
Lifespan: 5-8 years
Minimum Tank Size: 55 gallons
Tank Mate Compatibility: Middle or surface dwelling fish

Should You Keep The Red Tail Shark? (Summary)

A Red Tail Shark is a challenging but fun fish to keep.

While they do not get along well with other fish, you can keep them in a community tank if you are careful.

Just remember that although this is a small fish you will need to invest in a larger tank size and put in some extra work.

Although they can be aggressive, lots of people over exaggerate their personality. This leads to an undeserved bad reputation.

Even though they can be a handful they are not too difficult to handle.

When kept in a tank o their own they are very fun to watch as they prey just like a miniature shark. They are colorful enough to draw attention to even a single species setup too.

If you are looking to enter the world of freshwater sharks then the Red Tail is a great place to start. Does your Red Tail Shark live alone or in a community?

Let us know in the comments section below…