Rainbow Shark: Care, Tank Size, Diet, and More

also known as the Red-Finned Shark or Ruby Shark
Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: July 14, 2024
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Struggling to create the perfect tank environment for these sparkling swimmers? Look no further. This guide offers solutions to your aquarium challenges. Uncover tips to make your fish friends thrive and prosper. Learn about their tank size needs and favorite foods. With this detailed guide, you’ll build a safe home for your Rainbow Shark. **Say goodbye to confusion** and master fishkeeping. **Keep reading** for more tips.

Article Summary

  • Rainbow sharks have vibrant red fins and a sleek black body, with a distinctive bold black stripe along their body.
  • They are susceptible to common aquarium diseases, so maintaining excellent water quality and a balanced diet is important.
  • They can become stressed due to inappropriate tank conditions, poor water quality, or aggressive tank mates.

Rainbow Shark: A Freshwater Fish

The rainbow shark, also known as the Red-Finned Shark or Ruby Shark, is a popular freshwater aquarium fish native to Southeast Asia. Belonging to the Cyprinidae family, this variety of fish is sought after by many aquarium enthusiasts for its vibrant colors and unique appearance.

These fish are native to the rivers of Southeast Asia. In their natural habitat, these fish thrive in spacious environments with plenty of hiding spots, such as caves. The rivers in Southeast Asia provide them with ample space to swim and explore, allowing them to exhibit their natural behaviors.

It is essential to consider their natural habitat in Southeast Asia’s rivers. These fish are accustomed to living in spacious environments. Therefore, it is important for owners to replicate these conditions in their aquarium tanks by providing ample space and suitable hiding places.

Resemblance To Sharks

The physical resemblance of rainbow sharks to certain species of sharks is one of the most intriguing aspects of these freshwater fish. While they may not be true sharks, their appearance can often fool people into thinking otherwise. They have a sleek and streamlined body shape, similar to that of certain shark species. They also have a dorsal fin that runs along their back, resembling the iconic fin of a shark.

Additionally, their coloration, with a dark gray or black body and vibrant red or orange fins, further adds to their shark-like appearance. These physical features combined make this species an eye-catching addition to any aquarium, as they bring a touch of the ocean’s majesty to freshwater environments.

Natural Habitat

One important aspect to consider when keeping these fish in aquarium tanks is replicating their natural habitat. Providing them with ample space is crucial, as these fish are used to swimming in larger bodies of water.

In addition to space, it is essential to create suitable hiding places for rainbow shark in the aquarium. By providing caves or other hiding spots, it can establish their own territory and feel secure in their environment.

The water conditions in their natural habitat should also be replicated in the aquarium. Rainbow shark prefers slightly acidic to neutral water to mimic the warm tropical conditions they are accustomed to.

Overall, understanding the natural habitat of rainbow shark is crucial for their well-being in captivity. By providing them with ample space, suitable hiding places, and maintaining the appropriate water conditions, owners can ensure these beautiful fish thrive in their aquarium tanks.

Rainbow Shark Profile

Average Lifespan

In terms of lifespan, rainbow sharks have an average lifespan that can range from five to eight years when provided with suitable care. Several factors can affect their longevity, including water quality and maintenance. It is crucial for owners to ensure that they provide enough space and maintain appropriate water conditions for these fish to thrive.

Conservation Status

Rainbow sharks, also known as red-finned sharks, are not currently listed as an endangered species. This means that their population is not at immediate risk of extinction. However, it is important to note that their natural habitat in Southeast Asia, particularly the Xe Bangfai river, faces various threats that could potentially impact their long-term survival.

One of the main threats to to these freshwater species is pollution. The Xe Bangfai river, like many other water bodies in Southeast Asia, is heavily polluted due to industrial waste, agricultural runoff, and improper waste disposal. This pollution not only affects the water quality but also the availability of food sources for which rainbow sharks eat. It can lead to the decline in their population and overall health.

The destruction of their habitats disrupts their breeding and feeding patterns…

Habitat destruction is another significant concern for their conservation. Southeast Asia has seen extensive deforestation and land development in recent years, resulting in the loss of their natural habitats. The destruction of their habitats disrupts their breeding and feeding patterns, making it harder for them to survive and reproduce.

Additionally, the popularity of rainbow sharks in the aquarium trade poses a potential threat to their conservation. While they are bred in captivity, there is still a demand for wild-caught rainbow sharks, which contributes to the depletion of their populations in the wild. It is crucial for aquarium enthusiasts to support responsible sourcing practices and ensure that they are not contributing to the decline of wild rainbow shark populations.

Rainbow Shark’s Body

The rainbow shark is a captivating creature with its vibrant red fins and sleek black body. Its striking coloration makes it stand out among other aquarium fish. The slender and torpedo-shaped body of the rainbow shark adds to its graceful appearance. Growing up to 6 inches in length, this fish is relatively small compared to some other species commonly kept in captivity.

One of the most distinctive features of the rainbow shark is the bold black stripe…

One of the most distinctive features of the rainbow shark is the bold black stripe that runs horizontally along its body. This stripe gives it a unique and eye-catching look. It’s worth noting that rainbow sharks exhibit sexual dimorphism, meaning there are visible differences between males and females. Males tend to have a more intense coloration, especially in their fins, while females may appear slightly duller.


In terms of growth, rainbow sharks start off as tiny fry but quickly develop into impressive specimens within a short span of time.

Their growth rate largely depends on various factors such as water quality, diet, and overall health Providing them with a well-maintained tank environment and a balanced diet will contribute to their optimal growth.

Difference From Albino Rainbow Shark

In addition to their distinct coloration, there are a few other notable differences between albino rainbow sharks and their non-albino counterparts. One of the main differences is their behavior. Albino rainbow sharks tend to be slightly less aggressive fish than normal rainbow sharks. While both varieties can be territorial, albino rainbow sharks are generally more peaceful and less likely to engage in aggressive behavior towards tankmates. This makes them a better choice for community aquariums with other peaceful fish species.

Another difference lies in their overall appearance. As mentioned earlier, albino rainbow shark lacks pigmentation, resulting in a white body coloration. On the other hand, normal rainbow shark have a striking black coloration with vibrant red tail fins. This difference in appearance can be a deciding factor for aquarium enthusiasts looking for a specific aesthetic in their tanks.

Additionally, there may be slight variations in the size and growth rate between the two types. While both the albino rainbow shark and regular rainbow shark can grow to a similar size of around 6 inches, some aquarists have observed that albino rainbow shark tends to have a slightly slower growth rate compared to their non-albino counterpart. However, this difference in growth rate is not significant and may vary from individual to individual.


Albino rainbow sharks may be more difficult to find and may come with a higher price tag compared to regular rainbow sharks.

Lastly, it’s important to note that the availability of albino rainbow sharks in the aquarium trade may not be as widespread as regular rainbow sharks. This is because the albino variation is less common and may require specific breeding efforts to produce.

Overall, while albino rainbow shark and regular rainbow shark share many similarities in terms of care requirements and behavior, their distinct coloration and slight differences in aggression, appearance, size, and availability set them apart. Whether you prefer the vibrant red and black coloration of regular rainbow sharks or the unique white body of albino rainbow sharks, both varieties can make fascinating additions to a well-maintained tank.

General Behavior and Temperament

Red-finned sharks, known scientifically as Epalzeorhynchos frenatum, exhibit distinct behavior and temperament traits that make them fascinating additions to aquariums. Understanding their natural behavior in the wild and how it translates to captivity is crucial for providing them with a suitable environment.

Natural Behavior in The Wild

In their natural habitat, rainbow sharks are native to Southeast Asia, particularly Thailand. They inhabit freshwater rivers and streams with moderate water flow. These fish are known for their active nature and territorial tendencies. In the wild, they establish dominance over their territory and fiercely defend it against intruders.

Behavior in Captivity

Rainbow Shark Exploring The Tank

When kept in captivity, rainbow sharks retain their active behavior. They constantly explore their surroundings, searching for potential hiding spots or territories to claim as their own. It is essential to provide them with ample swimming space by choosing an adequately sized tank.

Aggressive Rainbow Shark

One notable aspect of the rainbow shark’s temperament is its aggression towards other fish of similar size and appearance. Due to their territorial nature, they are territorial fish that may perceive species of similar size and appearance as threats or competitors. Therefore, it is advisable to avoid housing rainbow shark with other fish that resemble them or have comparable body shapes.

Preference For Hiding Spots

To mimic the natural habitat of rainbow sharks, it is important to include suitable hiding spots within the aquarium setup. These fish prefer caves or driftwood where they can retreat when feeling threatened or simply seek solitude. Providing such structures not only caters to their behavioral needs but also helps alleviate any potential stress caused by constant exposure.

Community Tanks With Small Fish

Given the aggressive temperament of rainbow sharks towards similar species, it is not recommended to keep them in community tanks containing small or slow-moving fish. Rainbow sharks may view these smaller inhabitants as easy targets or potential prey due to differences in size and behavior, and rainbow sharks kill these small fish. So, it is crucial to prioritize the safety and well-being of all fish within the aquarium.

Rainbow Shark Care Guide

If you’re considering adding a rainbow shark to your aquarium, it’s important to understand the care requirements for this beautiful species. Rainbow sharks, also known as ruby sharks, are popular choices among freshwater fish enthusiasts due to their vibrant colors and unique appearance.

To create an ideal environment for rainbow shark, owners should set up large tanks with dimensions that allow them enough space to swim freely, and incorporating caves or other structures into the tank will help mimic their natural habitat. Owners should invest in a reliable filtration system that can handle the waste produced by these active fish. Regular monitoring of water parameters such as ammonia, nitrite, and nitrate levels is necessary to prevent any potential health issues.

Tank Setup

Ruby sharks are active swimmers that require ample space to move around comfortably. When setting up their tank, it is crucial to provide enough room for them to explore and swim freely. At least 55-gallon tank is recommended for a single rainbow shark.

Hardscape Considerations

When considering hardscape materials for your rainbow shark’s tank, it’s important to take into account their specific needs and behaviors. Rainbow sharks are active swimmers and enjoy exploring their environment, so providing them with suitable hardscape features is essential for their well-being.


When choosing hardscape materials for your rainbow shark’s tank, opt for items that won’t harm or injure them.

One important consideration is to choose materials that won’t harm or injure your rainbow shark. Smooth rocks and driftwood are excellent options as they provide hiding places while preventing any potential injuries caused by sharp edges or rough surfaces. It’s crucial to thoroughly inspect any rocks or driftwood before placing them in the tank to ensure they are free from any sharp edges or toxins that could be harmful to your fish.

In addition to safety, hardscape features should also be selected based on their functionality. Rainbow sharks are known to be territorial and may establish their own territories within the tank. Providing them with suitable hiding places, such as caves or crevices created by rocks or driftwood, can help alleviate any potential aggression or stress caused by territorial disputes. These hiding places also serve as natural boundaries and can help create a more harmonious environment for your rainbow shark and other tank mates.

Choose appropriately sized rocks and driftwood that won’t overcrowd the tank…

Consider the size and arrangement of the hardscape materials as well. Rainbow sharks are relatively large fish and require ample swimming space. It’s important to choose appropriately sized rocks and driftwood that won’t overcrowd the tank or restrict their movement. Creating a balanced and aesthetically pleasing arrangement of hardscape materials can also enhance the overall visual appeal of your aquarium.

Lastly, it’s essential to maintain proper water parameters and cleanliness when incorporating hardscape materials into your rainbow shark’s tank. Rocks and driftwood can sometimes affect the water chemistry, so regular monitoring of pH, hardness, and other water parameters is necessary. Additionally, hardscape features can accumulate debris and waste, so regular cleaning and maintenance is vital to ensure a healthy and clean environment for your rainbow shark.

Tank Mates

When it comes to selecting compatible tank mates for rainbow shark, there are several options to consider. Peaceful community fish like tetras, rasboras, danios, or barbs are generally good choices. These fish tend to be non-aggressive and can coexist harmoniously with rainbow sharks.

Tetras, such as neon tetras or cardinal tetras, are small and peaceful fish that make great companions for rainbow sharks. They add a vibrant pop of color to the tank and are known for their peaceful nature.

Rasboras, like harlequin rasboras or lambchop rasboras, are another suitable option. They are active and social fish that can create a lively and dynamic environment in the tank.

Danios, such as zebra danios or pearl danios, are known for their energetic and playful behavior. They are fast swimmers and can add a sense of activity to the tank, which can be stimulating for rainbow sharks.

Barbs, like cherry barbs or gold barbs, are peaceful and colorful fish that can coexist well with rainbow sharks. They are active fish that enjoy swimming in schools, which can create a visually appealing and engaging tank environment.

Aggressive or fin-nipping fish, such as cichlids or tiger barbs, can stress out rainbow sharks…

On the other hand, there are certain species that should be avoided as tank mates for rainbow sharks. Aggressive or fin-nipping fish, such as cichlids or tiger barbs, can stress out rainbow sharks and potentially lead to health problems. It’s best to steer clear of these species to ensure the well-being of your rainbow shark.

By selecting compatible tank mates and avoiding species that may provoke aggression or stress, you can create a peaceful and harmonious community tank for your rainbow shark.

Multiple Rainbow Sharks

Keeping multiple rainbow sharks together in a tank can be a challenging task. Rainbow sharks are known to be territorial and aggressive towards their own kind, especially when they reach maturity. Therefore, it is generally not recommended to keep multiple rainbow sharks in the same tank, unless you have a very large aquarium with plenty of hiding spots and territories for each and one rainbow shark.

Rainbow Sharks in a Tank

If you do decide to keep multiple rainbow sharks together, here are some tips to minimize aggression and territorial disputes:

Tank Size: Make sure you have a spacious tank with a minimum size of 55 gallons. The larger the tank, the better, as it provides more swimming space and reduces aggression.

Hiding Spots: Create plenty of hiding spots using rocks, caves, driftwood, and plants. This will help establish territories and provide areas for each shark to retreat to when feeling threatened.

Feeding: Ensure that all the rainbow sharks in the tank are getting enough food to reduce competition and aggression. Feed them a varied diet of high-quality pellets, frozen or live foods to meet their nutritional needs.


Every fish has its own personality, and there are no guarantees that multiple rainbow sharks will peacefully coexist. It’s essential to have a backup plan and be prepared to separate them if needed.

Monitor Behavior: Keep a close eye on the behavior of the rainbow sharks. If you notice any signs of aggression or stress, such as chasing, nipping, or torn fins, it’s best to separate them immediately to prevent further harm.

Water Parameters

Rainbow shark requires specific water parameters to thrive in an aquarium setting. Maintaining optimal water conditions is crucial for their overall well-being. One of the key factors to consider is the temperature of the water. Rainbow shark prefers a temperature range between 75°F and 80°F (24°C – 27°C). It is important to use a reliable aquarium thermometer to monitor and regulate the water temperature within this range.

In addition to temperature, the pH level of the water is also important for rainbow shark. It is recommended to keep the pH level within a range of 6.5 to 7.5. This range helps to create a suitable environment that mimics their natural habitat, ensuring their health and happiness.

To maintain these water parameters, regular water testing is essential. Using a water testing kit, you can monitor the temperature and pH levels of the aquarium water. If any adjustments are needed, it is important to make gradual changes to avoid stressing the fish.

It is also worth noting that rainbow sharks are sensitive to water quality. Regular water changes, typically around 25% every two weeks, help to remove any buildup of toxins and maintain a clean and healthy environment for the fish. When performing water changes, it is important to use a dechlorinator to remove any harmful chemicals from tap water.

By paying attention to the water parameters and making necessary adjustments, you can provide a suitable and stable environment for your rainbow shark. This will contribute to their overall health and ensure they thrive in their aquarium habitat.

Feeding Requirements and Diet

Rainbow sharks have specific feeding requirements and a diverse diet is essential for their overall health and well-being. While high-quality flakes or pellets formulated for freshwater fish should form the basis of their diet, it is important to supplement their meals with occasional live or frozen foods. This helps mimic their natural feeding habits and provides them with a variety of nutrients.

Live foods such as brine shrimp, bloodworms, and daphnia are excellent choices to include in their diet. These foods are rich in protein and are highly beneficial for rainbow sharks. They not only provide essential nutrients but also stimulate their natural hunting instincts.

In addition to live foods, it is also recommended to offer them a variety of frozen foods. Frozen brine shrimp, bloodworms, and daphnia are readily available and can be easily added to their diet. These frozen foods retain their nutritional value and are a convenient option for providing a diverse diet for your rainbow shark.

Specially formulated foods are designed to provide a balanced and complete diet for ruby sharks…

It is important to note that while live and frozen foods are important for their diet, they should not be the sole source of nutrition. High-quality flakes or pellets should still form the majority of their meals. These specially formulated foods are designed to provide a balanced and complete diet for rainbow sharks, ensuring they receive all the necessary vitamins and minerals.

Feeding frequency is another important aspect to consider. Rainbow sharks should be fed small amounts multiple times a day, rather than one large meal. This helps prevent overfeeding and allows them to digest their food more efficiently.

Common Diseases

Rainbow sharks, like any other aquarium fish, are susceptible to certain common diseases. It is important for fish owners to be aware of these diseases in order to prevent and treat them effectively.

One common disease that rainbow sharks can experience is ich, also known as white spot disease. Ich is caused by a parasite called Ichthyophthirius multifiliis, which attaches itself to the fish’s body and fins. Infected fish may display symptoms such as white spots on their body, increased scratching against objects in the tank, and rapid breathing. To prevent ich, it is crucial to maintain excellent water quality by performing regular water changes and keeping the tank clean. Additionally, maintaining a balanced diet for your rainbow shark can help boost its immune system and reduce the likelihood of contracting ich.

Another common disease that rainbow sharks may encounter is Fin-rot. Fin rot is a bacterial infection that affects the fins and tail of the fish, causing them to become ragged, frayed, or discolored. Poor water quality, stress, and injuries can contribute to the development of fin rot. To prevent fin rot, it is important to maintain a clean and well-filtered tank. Regular water changes and proper filtration can help keep the water conditions optimal for the fish’s health. If your rainbow shark does develop fin rot, treatment options include using antibiotics or antifungal medications, as prescribed by a veterinarian.

Fungal infections, bacterial infections, and parasites can cause a variety of symptoms…

In addition to ich and fin rot, rainbow sharks can also be susceptible to other diseases such as fungal infections, bacterial infections, and parasites. These diseases can cause a variety of symptoms, including lethargy, loss of appetite, abnormal swimming behavior, and changes in appearance. It is important to monitor your rainbow shark closely and seek veterinary advice if you notice any concerning symptoms.

Overall, maintaining excellent water quality, providing a balanced diet, and being vigilant about any changes in your rainbow shark’s behavior or appearance can help prevent and treat common diseases. Regular observation and prompt action are key to ensuring these fish’s health.

Breeding and Considerations

Breeding these fascinating fish of the cyprinidae family can be a challenging task compared to other fish species. Here are some important considerations to keep in mind when attempting to breed rainbow shark.

Male and Female Identification

Before embarking on the breeding process, it is crucial to distinguish between male and female rainbow sharks. Males typically have a slimmer body shape with vibrant colors, while females tend to be larger and display a rounder belly. Males often possess more pronounced dorsal fins compared to their female counterparts.

Breeding Process

To initiate breeding, it is essential to create specific conditions conducive for successful reproduction. Separate breeding tanks should be set up with appropriate water parameters, including temperature and pH levels suitable for rainbow sharks. These tanks should also contain hiding spots such as caves or dense vegetation where the fish can lay their eggs.

Spawning Behavior

Rainbow sharks exhibit unique spawning behaviors that indicate they are ready to reproduce. The male will actively chase the female around the tank, engaging in courtship displays such as flaring its fins and vibrating its body. Once the female is receptive, she will release adhesive eggs onto surfaces like rocks or plants within the breeding tank.

Egg-Laying and Fry Care

After laying her eggs, it is crucial to promptly transfer the female back to her original tank as rainbow sharks may consume their own eggs if not separated in time. The fertilized eggs will hatch within a few days, revealing tiny fry that require special care. It is recommended to provide a separate grow-out tank for the fry with appropriate filtration systems and regular water changes.

Challenges of Breeding

Breeding rainbow sharks poses several challenges due to their specific requirements and behaviors. One significant obstacle is ensuring optimal water conditions throughout the breeding process. Maintaining stable temperature levels between 77-82°F (25-28°C) and a slightly acidic to neutral pH between 6.5-7.5 is crucial for successful reproduction.

Another challenge is the potential aggression displayed by male rainbow sharks during the breeding period. It is important to closely monitor their behavior and intervene if any signs of excessive aggression or stress are observed. Providing ample hiding spots can help alleviate tension within the tank.

Where to Find Rainbow Sharks for Sale

If you’re looking to add a vibrant and eye-catching fish to your aquarium, the rainbow shark is an excellent choice. Known for its striking appearance and active nature, this freshwater species can be a captivating addition to any tank. But where can you find rainbow sharks for sale? Let’s explore some options.

Local Pet Stores

One of the most accessible places to find ruby sharks for purchase is your local pet store, especially those that specialize in tropical fish. These stores often have a dedicated section for freshwater species, including ruby sharks. Visiting these establishments allows you to see the fish in person and assess their health and vitality before making a decision. The staff at these stores are usually knowledgeable about the care requirements for these fish and can provide valuable advice.

Online Aquarium Retailers

The internet has made it easier than ever to find and purchase unique fish species. Numerous online aquarium retailers offer an extensive selection of freshwater fish, including red-finned sharks. Shopping online provides convenience as you can browse through different options from the comfort of your home. Make sure to choose reputable sellers with positive reviews and consider their shipping policies before placing an order.

Fish Auctions or Hobbyist Groups

For those who enjoy engaging with other aquarium enthusiasts, attending fish auctions or joining hobbyist groups can be an exciting way to find rainbow sharks for sale. These events bring together breeders and fellow hobbyists who may have bred their own rainbow sharks available for purchase. Not only will you have access to a variety of colors and patterns, but you might also learn valuable tips on caring for these beautiful creatures from experienced aquarists.

Breeding rainbow shark can be a rewarding experience for experienced aquarists, but it requires specific conditions such as the right tank setup, water parameters, and compatible mates. If you’re interested in breeding rainbow shark, consider researching specialized guides or seeking advice from seasoned breeders.

Frequently Asked Questions

Why is my rainbow shark stressed?

Rainbow shark can become stressed due to various factors, such as inappropriate tank conditions, overcrowding, poor water quality, or aggressive tankmates. It’s essential to ensure that your rainbow shark has enough hiding places, appropriate tank size (at least 50 gallons), and compatible tankmates to minimize stress levels. Regular water maintenance and monitoring water parameters can also help reduce stress.

Does rainbow shark like light?

Rainbow shark prefers moderate to low lighting conditions. While they do need some light for natural day and night cycles, excessive or intense lighting can cause stress and discomfort. Providing hiding spots and dimming the tank lights can create a more suitable environment for rainbow shark.

Does rainbow shark need bubbles?

Rainbow shark does not specifically require bubbles or air stones in their tank. However, they do appreciate well-oxygenated water. Utilizing a reliable filtration system, performing regular water changes, and maintaining appropriate oxygen levels through surface agitation should be sufficient for their needs.

How often do you feed a rainbow shark?

It is recommended to feed rainbow sharks once or twice a day. They are omnivorous and enjoy a varied diet consisting of high-quality flakes, pellets, and frozen/live foods. It’s important not to overfeed them, as it can lead to health issues and poor water quality. Monitor their feeding habits and adjust the portion sizes accordingly.

Are rainbow sharks sensitive to salt?

Yes, rainbow sharks are sensitive to salt, particularly marine salt. They are freshwater fish and should not be exposed to high levels of salinity. Adding marine salt or any form of salt intended for saltwater aquariums can be harmful and stressful for rainbow sharks. Keep their environment strictly freshwater and avoid adding salt unless under specific veterinary advice for treating certain health conditions.

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