Keeping Tropical Fish: How to Care for a Red-Tailed Shark

 

Red-Tailed Sharks are one of the most striking freshwater fish in the aquarium hobby. With their jet-black bodies and bright red tails, they quickly become the centre of attention in any tank. However, they are not just about looks, they also have specific care needs and a strong personality.

This guide will help you understand everything you need to know before keeping a red-tailed shark.

 

Red-Tailed Sharks (Epalzeorhynchos bicolor)

History and Origins

The Red-Tailed Shark (Epalzeorhynchos bicolor) originates from Thailand, specifically the Chao Phraya river basin. In the wild, Red-Tailed Sharks inhabit rivers and streams with sandy or rocky riverbeds.

When setting up an aquarium for one of these sharks, it’s a good idea to try to recreate this natural habitat as closely as possible. Using sand or fine gravels as substrate, along with rocks and pebbles alongside botanicals like catappa leaves, can help the fish feel more comfortable and settled in its new environment.

Sadly, they are now considered critically endangered in the wild due to habitat loss and pollution. Almost all Red-Tailed Sharks in the aquarium trade today are bred in captivity.

 

What Do Red-Tailed Sharks Look Like?

Red-Tailed Sharks are instantly recognizable thanks to their bold and striking appearance. They have a smooth, torpedo-shaped body that is usually deep black in colour, contrasted by a vivid red or orange tail. This dramatic colour contrast makes them a standout feature in many home aquariums.

Varieties

• Red-Tailed Black Shark – The classic variety, featuring a jet-black body with a bright red tail.

• Albino Red-Tailed Shark – A lighter variation with a white or golden body and the same distinctive red tail.

Red-Tailed Sharks are often mistaken for Rainbow Sharks, which have grey or dark bodies with red colouring on all fins. Despite their similar appearance, Rainbow Sharks are a different species with slightly different behaviour and care needs.

The intensity of a red-tailed shark’s tail colour can vary depending on factors such as overall health, diet, stress levels, and water quality. In many cases, the tail becomes more vibrant as the fish matures and settles into a well-maintained aquarium.

 

What Do Red-Tailed Sharks Eat?

Red-tailed sharks are omnivorous fish. In their natural habitat, they feed on a mix of algae, plant material, and small insects. To help them thrive in an aquarium, it’s important to provide a varied and balanced diet that closely reflects what they would eat in the wild.

In a home aquarium, their diet should include:

• High-quality sinking pellets (fed daily): These form the staple of their diet and provide essential nutrients needed for healthy growth and overall wellbeing.

• Algae wafers (offered a few times per week): These help increase fibre intake and support natural grazing behaviour.

• Occasional protein-rich foods such as bloodworms or brine shrimp: These replicate the insect protein they would naturally consume in the wild and can help enhance colouration.

A varied diet helps maintain vibrant colours and supports a strong immune system. Protein can be provided through different food types, including frozen, freeze-dried, or live options.

Offering a range of foods not only meets nutritional needs but also provides enrichment and keeps the fish more interested and engaged during feeding time.

 

Compatibility: Tank Mates

Red-Tailed Sharks are territorial and can become increasingly semi-aggressive as they grow older. For this reason, they should be housed with tankmates that are quick, confident swimmers and less likely to be intimidated.

They are best kept singly in the aquarium as the only Red-Tailed or Rainbow Shark; however, with carefully chosen tankmates, they can still live peacefully in a community tank alongside compatible species such as:

 

Good Tank Mates

• Fast-swimming fish (Denison barbs, Tiger barbs, Golden Barbs etc)

• Larger tetras (Widow Tetra, Phantom Tetra, Buenos Aires Tetra etc)

• Danios

• Rainbowfish

These are just a few examples of fish that can be kept with Red-Tailed Sharks. If you’re considering adding one to your aquarium or are unsure about compatibility with a particular species, feel free to get in touch with our team at Complete Koi & Aquatics for friendly advice and guidance.

 

Fish to Avoid

• Other Red-Tailed Sharks or fish that look similar such as Rainbow Sharks (They will fight!)

• Slow or long-finned fish (Bettas, Angelfish)

• Smaller species that may fit in the mouths of an adult shark as they may be mistaken for food. 

It’s important to remember that these fish are territorial, so make sure your aquarium provides enough space for the shark to coexist peacefully with its tankmates. Adding a dedicated cave or hiding spot can also help reduce aggression and give the fish a sense of security within the aquarium..

 

Important Factors for Care

Caring for Red-Tailed Sharks is generally similar to looking after other community tropical fish. They do best in a well-maintained aquarium with stable water conditions and ample space.

Keep reading to learn everything you need to know to ensure your red-tailed shark thrives and stays happy in your tank.

 

Water Quality

Clean water is essential. Poor water quality can cause stress, faded colours, and illness. The best approach is prevention. Testing your water regularly with a reliable test kit ensures any problems are caught and treated early.

For the best health, Red-Tailed Sharks do well under the following water conditions:

• Ammonia: 0 ppm

• Nitrite: 0 ppm

• Nitrate: below 20–30 ppm

• pH: 6.5–7.5

• Hardness: 4–6 dKH

Conducting weekly water changes of 10–20% and using a gravel vacuum helps to remove excess waste, keep nitrate levels low, and replenish vital minerals.

Be sure to treat new water with a dechlorinator before adding it to the tank. By maintaining a regular routine of water testing and water changes, you provide your aquarium’s inhabitants with the cleanest and healthiest environment possible.

 

Tank Size

• Minimum tank size: 200 Liters

Red-Tailed Sharks are naturally territorial and need ample space to establish their own territory. Keeping them in a tank that is too small can intensify aggressive behaviours.

While juvenile red-tailed sharks start out small, they can quickly grow to reach sizes of up to 6 inches (15 cm). For this reason, they require a sufficiently large tank to thrive comfortably and reduce stress.

Because of their streamlined body shape and active swimming style, red-tailed sharks do best in tanks that are longer rather than tall. This layout allows them to swim freely, explore their environment, and display natural behaviours without feeling cramped. Providing enough horizontal space is essential for their physical and mental well-being.

We recommend the following aquariums for Red-Tailed Sharks:

• Fluval Roma 200 Aquarium & Cabinet

• Juwel Rio 240 Aquarium & Cabinet

• Aquatlantis Splendid Ultra 100 Aquarium

For more options, check out our full range of aquariums [here] to find the perfect setup for your Red-Tailed Shark.

 

Heating & Temperature

Red-Tailed Sharks are tropical fish and need a consistently warm environment, ideally between 23°C and 27°C. To maintain this temperature, the aquarium should be equipped with a heater and a thermometer.

Most aquarium heaters include a built-in thermostat that helps regulate the water temperature; however, it is still strongly recommended to have a thermometer in the tank so you can easily and accurately monitor the water temperature at all times.

 

Tips for Keeping Your Shark Happy

• Provide plenty of hiding spots using caves, driftwood, and plants. Make sure all hiding spaces are large enough for your fish to fit comfortably and upgrade them as the fish grows.

• Keep lighting moderate to reduce stress. In the wild, these fish come from murky riverbeds with low light levels. Bright lighting can cause stress, especially if the fish has no shaded areas to escape to.

• Maintain a regular feeding schedule and offer a varied diet to ensure your fish receives all the nutrients it needs to thrive.

• Avoid overcrowding. While Red-Tailed Sharks can live with a variety of other fish species, they are best kept singly, as this reduces territorial behaviour and prevents aggression between sharks.

• Monitor behaviour closely. Increased aggression can be a sign of stress; identifying and addressing the cause will help keep your fish calmer and a better tank mate overall.

One of the most important things you can do is maintain a consistent tank maintenance routine. A clean, well-maintained aquarium supports a healthier, more active fish and will also look better in the long term.

 

Thinking about adding a Red-Tailed Shark to your tank?

Red-Tailed Sharks are striking and fascinating fish, but they aren’t always the best choice for beginners. Before bringing one home, be sure you can meet their space, care, and temperament needs. If you’re prepared for the challenge, a Red-Tailed Shark can be a bold and rewarding addition to your aquarium.

Take the time to research thoroughly, plan your setup carefully, and provide this iconic fish with the environment it needs to thrive.

For more information and advice on aquatics, check out the rest of our blogs…

Keeping Tropical Fish: The Colourful World of Swordtail Fish | Keeping Tropical Fish: How to care for Silver Sharks | Are Denison Barbs Right for Your Tank? A Simple Care Guide