Red Tail Shark: Your Ultimate Care Guide

Red tail shark (Epalzeorhynchos bicolor) is a freshwater aquarium fish from Cyprinidae family. The red tail shark is definitely not for community tanks due to its aggressive behavior towards its tank mates. It’s quite unusual and not demanding fish that attracts attention with its rare body coloring – contrasting combination of almost black and red colors.

Habitat in the wild

The red tail shark (Epalzeorhynchos bicolor), despite its name, it is not a true shark but rather a member of the family Cyprinidae. This family includes a wide range of fish species commonly referred to as “carps” and “minnows.” The red tail shark is a part of the subfamily Labeoninae, which consists of various barb-like fish.

The red-tailed shark is endemic to shallow algous ponds of Thailand with clean flowing water (for example Chao Phraya – the Mekong River tributary). In their natural habitat, they are typically found in slow-moving or stagnant freshwater rivers, streams, and flooded areas with dense vegetation and rocky substrates. These areas often have plenty of hiding spots, which the red tail sharks use to establish territories and defend against other individuals.

Some specific habitats for this species are unknown; however, other species inhabit in rivers and streams or migrate to forests and bottom-lands during raining season. This migration connected with the fish spawning period is assumed to be disturbed nowadays as a result of human intervention. Therefore, the red tailed shark population in the wild has decreased drastically.

Though, they say that the reason for this is, first of all, excessive capture of the fish for the aquarium trade, nevertheless the negative impact of the environmental changes is considered to be more probable cause, for example, it may be the damage done by dam construction and bog reclamation.



The Epalzeorhynchos bicolor typically grows to a size of around 4 to 6 inches (10 to 15 centimeters) in length when kept in a home aquarium. However, in the wild, they can potentially grow slightly larger.


The average lifespan of a red tail shark is typically around 5 to 8 years in a well-maintained aquarium. However, with proper care and a suitable environment, some individuals may live even longer, possibly reaching up to 10 years or more.

Several factors can influence the lifespan of a red tail shark, including water quality, diet, tank size, and overall care. Providing them with a balanced diet, a spacious and well-maintained tank, and keeping stress levels low can help ensure they live a healthy and fulfilling life.


Body is slim, elongated and flattened from sides with curved back. On the red-tailed shark small head there is a pair of large red eyes, its inferior mouth has two pairs of barbs and setules, it is cupule- shaped and the fish uses it to scraper different organisms and algae from the tank bottom.


The main coloring is velvet black, its fins are large and also black – the dorsal is high and sharpened, while anal, abdominal and pectoral fins are transparent and well-developed. The fluke is bright red, long and bifurcated.

Scientific NameEpalzeorhynchos bicolor
Common NameRed Tail Shark, Redtail Sharkminnow
FamilyCyprinidae (carp and minnow family)
HabitatFreshwater rivers and streams in Southeast Asia
SizeUp to 6 inches (15 cm) in length
Lifespan5 to 8 years in captivity
AppearanceDeep black body with a bright red or orange tail fin
BehaviorCan be territorial and aggressive, especially towards its own kind
DietOmnivorous – eats algae, small crustaceans, and fish flakes or pellets
Tank RequirementsRequires a well-oxygenated tank with hiding spots and plenty of swimming space
Tank SizeAt least 30 gallons for a single individual
CompatibilityAvoid keeping with other territorial or fin-nipping fish
Temperature Range72°F to 79°F (22°C to 26°C)
pH Range6.5 to 7.5
Water Hardness5 to 12 dGH
BreedingDifficult to breed in captivity
Conservation Status*Not listed on the IUCN Red List (as of September 2021)

Difficulties in keeping

There’s nothing difficult as for red tailed shark care, but the fish is quite large and it has aggressive temper. Therefore, it can’t be recommended to the beginners and it shouldn’t be kept in small tanks.

Care and keeping in a tank

Tank size

The red tail shark (Epalzeorhynchos bicolor) requires a spacious aquarium to thrive. For a single fish, a minimum tank size of 30 gallons (113 liters) is recommended. This provides enough swimming space and allows the fish to establish its territory.

It’s important to note that red tail sharks can be territorial and aggressive towards their own kind and other similar-looking fish, so it’s generally best to keep only one individual in the tank. Keeping multiple red tail sharks together can lead to aggressive behavior and stress.

If you plan to keep more than one red tail shark, you would need to increase the tank size to accommodate their territorial behavior and provide enough space for each fish to establish its territory. It’s generally recommended to keep only one red tail shark in a standard-sized aquarium to avoid conflicts.

Additionally, when setting up the tank, provide plenty of hiding spots and create a well-oxygenated environment with proper filtration and water movement. Adding driftwood, rocks, and artificial plants can create suitable hiding places for the fish, which can help reduce stress.

Tank decor

Despite the fact that the fish requires sufficient number of places to hide, it is not demanding as for the tank decorations and it doesn’t harm any tank plants with soft leaves. However, it’s recommended to recreate natural habitat in a tank, i.e. a fast flowing river with bottom substrate of different size.

You may use gravel, stones and pebbles as a tank substrate and also put some tree roots and braches into the tank as well as water plants of Microsorum, Bolbitis or Anubias kind, which can stick to tank decorations.

Bright light will ensure active growth of algae, which is necessary for diet. Just like other species that inhabit in fast rivers the fish can’t stand accumulation of organic precipitate in the tank, since the fish prefers clean water with high oxygen content and moderate stirring.

Water parameters

Optimal water parameters for red-tailed shark keeping are the following:

  1. Temperature: 72°F to 79°F (22°C to 26°C)
    Red Tail Sharks prefer tropical water temperatures within this range.
  2. pH Level: 6.5 to 7.5
    Keep the pH of the aquarium water slightly acidic to slightly alkaline.
  3. Water Hardness: 5 to 12 dGH (degrees of General Hardness)
    Aim for a moderate hardness level in the water. Soft to moderately hard water is suitable.
  4. Ammonia and Nitrite: 0 ppm (parts per million)
    Ammonia and nitrite are toxic to fish, so it’s crucial to maintain these levels at zero. Regular water testing and appropriate filtration are essential to achieve this.
  5. Nitrate: Below 20 ppm
    Nitrate is a less toxic byproduct of the nitrogen cycle, but elevated levels can still be harmful. Regular water changes help keep nitrate levels in check.
  6. Dissolved Oxygen: Well-Oxygenated
    Red Tail Sharks need well-oxygenated water to thrive. Proper water circulation, aeration, and surface movement are necessary to maintain adequate oxygen levels.

It’s important to regularly monitor the water parameters using appropriate testing kits and promptly address any issues that arise. Consistent water changes and a well-maintained filtration system are crucial for keeping the water quality optimal for your fish health. Additionally, avoid sudden fluctuations in water parameters, as they can stress the fish and make them more susceptible to diseases.


Do red tail sharks eat algae? Yes, in the wild, they are considered omnivores, and a significant part of their diet consists of algae and other plant matter. You may often see how this fish scrapes algae from stones in the tank, but the fish prefers diversified feed with vegetable additives. You may feed the fish with some daphnia, blood worm, brine shrimp in combination with high quality dry feed and some vegetable food (cucumber, green peas, peeled squash, spinach, sliced fruits).

Here are some suitable foods for a red tail shark:

  1. High-quality fish flakes or pellets: These should be the staple food for your red tail shark. Look for products specifically designed for tropical fish and ensure they contain a mix of plant-based and protein-rich ingredients.
  2. Algae wafers or spirulina-based foods: Red tail sharks have a natural inclination to graze on algae, so offering algae-based foods can be beneficial for their health.
  3. Frozen or live foods: Occasionally, you can supplement their diet with live or frozen foods such as brine shrimp, bloodworms, daphnia, and mosquito larvae. These provide additional protein and variety in their diet.
  4. Fresh vegetables: They also enjoy certain vegetables like blanched zucchini, spinach, or cucumber. These can be clipped to the side of the tank or weighed down so that the fish can nibble on them.
  5. Occasional treats: You can provide occasional treats like small pieces of cooked fish or shrimp, but these should not make up the majority of their diet.

Remember to feed them in moderation and avoid overfeeding, as red tail sharks are prone to obesity. Feed them 1-2 times a day, only giving them an amount they can consume within a few minutes.

Tank mates

Though red-tailed shark is sold as a fish for community tanks, in fact, it isn’t so. However, it doesn’t mean that the fish should be kept separately; it just means that you should more carefully choose tank mates.

Juveniles are very timid and they tend to hide in some dark tank corners, while the adult species are rather territory dependent and behave aggressively towards their tank mates that look like them. Some species are more aggressive, than others.

You should exclude bottom dwelling fish (such as cichlids and the majority of catfish species) from the list of tank mates, since they may be attacked by the fish. To occupy upper water layer in the tank you should choose small active schooling fishes.

Ideally, it’s better to put red tail shark the last into the tank. Probably, in the wild this fish prefers solitary way of life and they get together only for spawning season. In captivity this instinct is preserved and it gets stronger, therefore it’s better to keep the adult alone.

In a very large tank with large number of hide-places it’s possible to keep several red tail shark species, however each fish will require at least 1 meter of the tank length.

Then who can get on well with red-tailed shark? These are characin and carp species, small and fast fishes. All these fishes are too fast for red tail shark to catch them and they inhabit in upper and middle water layers. For example: glowlight tetra, emperor tetra, rummy nose tetra, cardinal tetra, neon tetra.

Gender differences: male vs female

You almost can’t see between red tail shark male and female. Unlike some other fish species, red tail sharks do not exhibit significant physical differences between males and females. There are no external features or coloration patterns that reliably differentiate the sexes.

As red tail sharks mature and enter breeding condition, males may develop slightly slimmer bodies, while females might appear slightly rounder, especially when carrying eggs. However, these differences can be subtle and challenging to discern, making it difficult to visually sex them with certainty.

In most cases, the best way to determine the sex of a red tail shark is through behavioral observations during the breeding season. Males may display more aggressive and territorial behaviors when establishing territories and competing for mates. Female red tail sharks may show behaviors related to egg-laying and parental care if they successfully spawn.

If you are specifically interested in obtaining a male or female for breeding purposes, it’s recommended to purchase a group of young red tail sharks and observe their behaviors as they mature. This will allow you to identify potential pairs or individuals showing signs of breeding behavior.

However, if breeding is not your primary goal, it is perfectly fine to keep a single red tail shark in an aquarium, as they are generally territorial and may not do well in groups. Always ensure that your tank setup meets their needs in terms of space, hiding spots, and water quality, regardless of their sex.


As far as it is known this species doesn’t breed in captivity in private tanks, however the fish is bred on the farms where they use hormones for this. It is supposed to be possible to keep the number of red tail shark population in the wild only due to the farms.

Despite the fish high popularity among aquarists, it’s quite seldom kept in ideal conditions. Juveniles are usually sold without providing its owners with full information about the behavior and temper, its size when it becomes an adult fish and that its life span equals to about 8 years.

Quite often red-tailed sharks are sold as algae eaters. But keep in mind that, though the fish eats algae, it does this in smaller amounts than Crossocheilus species, therefore red-tailed shark won’t do as a tank cleaner.