Red Tail Sharks: Size, Care Guide, Tank Mates, Breeding, and More

Red Tail Sharks are popular among aquarists because of their aesthetic appeal and shark-like resemblance. Their striking appearance isn’t common. They are also territorial and hardy, making their care requirements moderately difficult.

When deciding whether to add a Red Tail Shark to your aquarium, you should know what the fish needs to survive. Understanding the fish’s temperament, behavior, and breeding mechanisms is also crucial.

This guide will help you learn everything about Red Tail Sharks, from what they eat to their best tank mates. Let’s dive right in.

Scientific Classification

Scientific Name: Epalzeorhynchos bicolor
Common Names: Red-tailed black shark, Red-tailed Labeo, or Redtail sharminnow
Genus: Epalzeorhynchos
Family: Cyprinidae

History and First Sighting

Also referred to as Redtail Shark Minnows, Red Tail Sharks originate from Thailand’s Chao Phraya basins. Their natural habitat includes rivers, creeks, and water streams with sandy or rocky substrates.

The fish were widely considered extinct until 2011. After that, massive captivity breeding began as their demand in the aquarium community peaked. Today, you will likely find captive-bred Red Tail sharks at your local aquarium fish store.

Species Overview

The Red Tail shark is a freshwater fish in the Cyprinidae family. It has a black coloration on its entire body except for the caudal fin, which is colored red.

The first sightings of red tail sharks were in Bueng Boraphet, a swamp and freshwater lake area at the center of Thailand. Most of the streams trickling out from Bueng Boraphet contain small populations of this fish.

Getting a Red Tail shark is a good idea if you are ready to take care of it. It helps ensure the fish doesn’t go extinct in the fishkeeping community.

It’s advisable to source it from a reputable breeder to ensure it’s been brought up in proper conditions and is healthy. Stay away from shops or breeders selling the fish at very low prices since the fish may be poorly cared for or sick.

Red Tail Shark Lifespan

Red Tail Sharks reach a length of 6 inches upon maturity, with a lifespan ranging from five to eight years in captivity. While males and females have similar lifespans, the females are wider and larger than their male counterparts.

A spacious aquarium and optimum water parameters can help the fish live a longer and more fulfilling life. The lifespan may also increase if you choose the right tank mates for the fish and only get them from a reputable breeder or seller.

The Appearance of Red Tail Shark

As the name suggests, Red Tail Sharks have a unique-looking red tail and shark-like appearance. They are also very aggressive and territorial toward other fish. Here’s what you should know about their distinctive features and size.

Distinct Features (Colors, Patterns, Fins)

Red-tailed Sharks have streamlined shark-like jet-black bodies with red tails. Their distinctive features include a triangular-shaped dorsal fin and pointed snout. It’s also common to find a red-tailed shark with a white top on the surface of the dorsal fin.

The red hue on the tail may start vanishing if the fish is sick, stressed, or exposed to poor water conditions. It is brighter in male adult fish, with a more pointed dorsal fin and slimmer bodies than their female counterparts. These differences are easily noticeable when the fish are 15 months old.

While Rainbow and Red Tail Sharks both have red tails and belong to the same family, the coloration of their tails differs. In particular, the fins on Rainbow Sharks are red, while those on Red Tail Sharks are black.


A healthy Red Tail Shark can measure 4 to 6 inches in length upon maturity. The length achieved relies on the level of care the fish receives and genetic factors. So, if you meet the care requirements of the fish, expect it to grow longer when mature.

How to Take Care of Red Tail Sharks


Due to their hardy nature and aggressiveness, Red Tail Sharks have moderately complex care requirements. The fish will feel comfortable, secure, and happy if you replicate the elements of their natural habitat in the aquarium. The care requirements include:

Food and Diet

The down-turned mouth of a red-tailed shark makes scavenging for food and feeding easier. It helps the fish scrape algae from sand or rocks or feed on worms, plant matter, crustaceans, and insects.

A Red-tailed Shark’s diet can consist of frozen or live foods, pellets, and vegetables such as blanched peas and zucchini. Since live food can make the coloration on the fish appear more vibrant, adding them at set times in the aquarium is a good idea. Frozen and live food options include brine shrimp, daphnia, and bloodworms.

Feed the fish once every two days, in the morning and evening. Go for food that easily sinks, such as pellets. And if you are feeding the fish vegetables, remember to cut them into small pieces so they can easily be consumed.

Since Red-tailed sharks aren’t quite picky with food, you may overfeed them without noticing. As you feed them, please pay attention to their behavior. If they do not consume everything you give them in one feeding session, you are likely introducing too much food to the tank. Excess uneaten food can interfere with the water pH levels and make your fish prone to illness.

The Right Tank Size

Opt for a 55-gallon elongated tank to house your Red Tail Sharks. An elongated tank makes it easier to increase oxygen levels in the water and creates more exploration room since the fish need ample space to move. Moreover, it can reduce the likelihood of aggression if you house the fish with others. If you fail to provide them with enough space, Red-tailed Sharks may get territorial and fight their tank mates.


Red Tail Sharks are predominantly nocturnal freshwater creatures requiring medium to low light in their tanks. Lowering the brightness levels helps the fish adjust to daytime activity. You may also add floating plants to the aquarium for shade.

Red tail sharks tend to hide under harsh lighting conditions or direct sunlight. Keeping the aquarium on a slightly darker side helps get the fish out of hiding.

Recommended Water Parameters

For optimal survival, Red-tailed Sharks need certain water parameters in an aquarium. The preferred water conditions include:

  • Water type: Freshwater but with regular changes done partially to keep the parameters optimal and maintain cleanliness.
  • Water temperature and acidity: 72°F to 79°F (22°C to 26°C) and pH levels of between 6 and 8
  • Water hardness: between 5 and 15 dGH

You’ll also need a small air stone (weighted bubbler) to diffuse air uniformly into the tank, a water heater to maintain warm water temperatures consistently, and a weighted lid to keep the fish from jumping out of the aquarium

Even though Red Tail Sharks aren’t very sensitive to their surroundings, checking the water parameters helps ensure that they live in sanitary conditions. As a result, your fish will lead healthy lives with reduced incidences of diseases. You can invest in a good-quality aquarium testing kit to monitor water parameters easily.

What do Red Tail Sharks Need in Their Tank

Red-tailed Sharks thrive in fast-moving streams filled with rocky substrate and dense vegetation. The water needs high amounts of dissolved oxygen to support the survival of this fish.

As you decorate the tank, try replicating the fish’s natural habitat as much as possible. You may use driftwood, caves, or fine-leaved plants to offer the fish safe hiding spots. These materials also give the fish ample space to set up territories.

Floating plants such as hornwort, water wisteria, and java moss are great additions to the tank since they help block too much light. Pebbles and rocks of different sizes help mimic the fish’s natural habitat, while a dark-hued substrate improves comfort in the tank, allowing the fish to show off its magnificent red tail.

Though fine gravel works in most tanks, it won’t work with a Red Tail fish, as it can be ingested by the fish while scavenging.

Filter System

Equip your aquarium with a filter that generates strong currents since Red-tailed Sharks are used to quick-flowing streams. They also like to swim against the current to expel energy.

Common Potential Diseases

Red Tail Sharks are prone to Ich (parasitic disease) and fin rot (bacterial infection). However, you can prevent these diseases by maintaining optimum water parameters and providing the fish with a healthy diet. Regular water changes can also help prevent these conditions.

If you are not keen enough, you may not spot signs of illness in your fish early. And when you do spot them, it may be too late to take action. The common symptoms Red-tailed Sharks may exhibit include deterioration of fins or scales, sudden change in their swimming patterns, lethargy, and loss of appetite.

When your fish develops Ich, it may have salt-like white spots on the body and flashing on the sides where it rubs against objects in the tank. Other symptoms of the disease include appetite loss and loss of activity.

If there’s an outbreak of Ich in your tank, quarantine the affected fish in a tank with high sanitary conditions. You should also gradually increase the water temperature by a few degrees to eliminate the parasite.

Red-tailed Sharks are likely to develop fin rot when surrounded by unsanitary water conditions or if they don’t have enough oxygen. Common symptoms of this infection include inflammation at the bottom of the fins, loss of coloration, and frayed and tattered fins. While you may treat fin rot using antibiotics, maintaining the appropriate water parameters and keeping the water clean is the best approach to handling the situation.

Behavior and Temperament


Red Tail Sharks are more active at night due to their nocturnal nature. Being bottom-feeders, Red-tailed Sharks like darting around the bottom of the aquarium. Their playful nature and impressive swimming abilities make them efficient at hunting food in natural habitats.

It’s incredibly fun to watch these freshwater fish move around the water. You’ll mostly spot them making their way to the tank’s bottom and darting away to find more interesting areas. Giving them a properly-sized tank and properly setting up the habitat can give them more room to roam.

Regarding other fish, adult Red Tail sharks portray an aggressive personality and are territorial. They like bullying small, slow-moving fish, whether playing or battling it out for food. They will also chase and harass any fish entering their spaces.

The best way to reduce this aggressive behavior is to provide plenty of vegetation and hiding spots. It would help if you also kept them with peaceful fish species. Separate Red Tail Sharks from other fish species if the aggression reaches unbearable levels. Isolation works well since they enjoy staying in captivity alone.

The juvenile ones are less aggressive than adult ones and need plenty of hiding spaces to feel comfortable and safe.

Best Tank Mates

Due to their aggressiveness, Red-tailed Sharks only pair well with certain fish species. So, rethinking the right tank mates is a good idea if you add these fish to your aquarium.

Bottom-dwelling, aggressive, or overly curious fish won’t pair well with them. They may have territorial issues and start fighting over food and territory.

Fish species that are peaceful and like spending most of their life close to the surface of the water are compatible. However, there’s no guarantee that the red-tailed sharks will maintain a peaceful temperament with the fish.

Nevertheless, the best tank mates include the following:

  • Bala Shark
  • Neon and Congo Tetra
  • Gourami (Sparkling, Honey, Pearl, and Dwarf)
  • Zebra and Giant Danios
  • Tiger, rosy, and tinfoil Barbs

Whether you want to keep Red-tailed Sharks with other fish or alone in the tank, it all boils down to the amount of space. Give your fish plenty of space to maneuver the water and scavenge for food. You should also have only a few fish to prevent conflicts or fights.

Red-tailed Sharks enjoy bullying slow-moving, long-finned, small, and timid fish like bettas, fancy guppies, and angelfish. Keeping them together in the tank is, therefore a bad idea. You should also not have invertebrates as tank mates since the Red Tail Sharks might feed on them.

Keeping Red Tail Sharks Together

Unless the aquarium is large enough for each occupant to have their territory, never house Red-tailed Sharks together. It’s because they like living in isolation. Otherwise, prepare for the risk of keeping more than one Red-tailed Shark in the same tank. For instance, there’s a high chance that the fish will engage in intense territorial wars.

If you keep Red Tail Sharks together, rear them in groups of four. Consider their maximum length at maturity when choosing an ideal tank size.

Red Tail Shark Breeding

Red Tail Sharks are readily available in the pet trade because their breeding occurs in commercial farms with highly controlled conditions. In these facilities, breeders use certain hormones to facilitate breeding.

Naturally, female Red-tailed Sharks lay the eggs. They can be quite aggressive, making the breeding process difficult for beginners. However, through observation, some bit of training, and the right equipment, it’s less of a hassle.

With the right tank size in place, maintain a higher female-to-male ratio. Additionally, provide the following conditions:

  1. Decorate the tank with driftwood and rocks to provide the fish with plenty of space to hide and lay eggs.
  2. Add a variety of live plants in the aquarium to imitate their natural habitat.
  3. Use a submersible aquarium heater to keep the temperatures in the range of 79 to 82 degrees Fahrenheit and a sunken thermometer to monitor the temperature.
  4. Maintain pH levels of 6.5 to 7.6 and add peat moss to the tank to acidify the water if you are dealing with soft water.
  5. The breeding pair of Red-tailed Sharks should remain in the tank after spawning. You should then observe them closely to determine if they will care for the eggs and remove them from the tank if they don’t.
  6. It takes two or more days for the fry to hatch fully and several more days to swim freely in the water. They are usually ready to eat after consuming the remainder of the yolk sacs. At this stage, feed them multiple foods and see what they respond to best.

Gender Differences

It’s hard to determine the gender differences between Red-tailed Sharks if you are not keen. To distinguish a male from a female, check the coloration of the stomach. The males have solid black stomachs, while the females have grayer ones. The females are also slightly larger and have a curved dorsal fin, while the males are slender.

Final Thoughts

A Red-tailed Shark is a stunning freshwater fish with a fierce personality and shark-like appearance. With proper care and tank conditions, the fish can live longer.

The increased captive breeding of this fish indicates that they will continue being popular in the fishkeeping community for a while giving you a chance to get one for your aquarium.