Rainbow Shark Care Guide: Everything You Need! (May 2024)


Rainbow Shark Care Guide: Everything You Need! (May 2023)

Every fish sold as a freshwater “shark” may look similar, with cigar-shaped bodies and pointed fins. But rest assured, the Rainbow Shark and its cousins are actually much more closely related to Goldfish!

These sharks aren’t fish-eaters, though they can have a bit of a temper at times. But they are still good community fish for beginners with medium sized aquariums!

In this guide, we’ll dive deep into the world of Rainbow Sharks, covering all the bases and answering all those burning questions you’ve got swimming around in your head.

By the end of this aquatic adventure, you’ll be a Rainbow Shark whisperer, ready to provide the finest care to your finned friends.

So grab your snorkel, put on your fins, and let’s get swimming with the Rainbow Sharks!

Rainbow Shark Care and Information

  • Scientific Name: Epalzeorhynchos frenatum
  • Adult Size: 6 inches
  • Temperament: Semi-aggressive; Territorial
  • Lifespan: 5-8 Years
  • Care Level: Beginner
  • Water Temperature: 75-80℉
  • Appearance: Elongated Grey body with Pale Pink, Orange, or Red Fins
  • Water pH: 6.0-7.5
  • Diet: Omnivorous
  • Tank Size: 30 Gallons

Overview of Rainbow Sharks

Rainbow Sharks are often sold in aquariums with dozens of individuals but they are fairly anti-social fish. They prefer being kept solitary and need a space to call their own, such as a cave or driftwood grotto.

Once they have a secure home, Rainbow Sharks will chase fish that try to enter but are otherwise peaceful towards their neighbors. It’s sharks that don’t have a cave that become a problem since they may decide to claim the entire bottom of the tank as their turf and start relentlessly chasing their tank mates.

WARNING: as they grow older Rainbow Sharks become more and more intolerant of each other and even if they have multiple caves, they will fight to the death in all but the largest of tanks (75+ gallons)

Rainbow Shark Appearance

Rainbow Sharks are usually sold in either their wild-type or albino color morphs, both of which are very attractive. Wild-type sharks have a slate grey to pale black color, with fins that range from pink or orange, but are occasionally bright red.

As the fish grows older, the colors may grow brighter or darker, depending on its sex and genetics. Albino Rainbow Sharks are a yellowish white with bright red eyes and fins. They maintain this appearance throughout their lives.

How Long Do Rainbow Sharks Live?

Rainbow Sharks have a solidly average lifespan of 5 years. When well cared for, these fish can live up to 8 years old!

How Big do Rainbow Sharks Grow?

Five to six inches is normal for Rainbow Sharks of both sexes. They are slightly smaller than Red-Tail Sharks (Epalzeorhynchos bicolor) and much smaller than the Black Shark (Labeo chrysophekadion).

Sexing Rainbow Sharks

Male and female Rainbow Sharks grow to be the same length.

However they have slight differences in appearance: males are significantly slimmer even if the female isn’t carrying eggs. Male Rainbow Sharks usually have brighter fin colors as well; intense red fins in an adult means you almost certainly have a male!


Optimal Water Conditions for Rainbow Sharks

Rainbow Sharks are from lowland parts of tropical Southeast Asia (Thailand, Vietnam) where the water temperature rarely gets below the mid-70’s. Therefore the water temperature should stay at around 75-80℉, increasing it further if the Rainbow Shark shows signs of disease or stress. Cooler water conditions slows their metabolism dangerously low, inviting infections from ich or bacteria.

As Southeast Asian natives Rainbow Sharks prefer acidic and neutral water chemistry but also do well in slightly alkaline conditions (pH 6.0-7.5). They are also hardy enough to withstand temporarily elevated levels of ammonia, nitrite, and nitrate.

Still, these parameters should be regularly monitored to avoid illness from the background stress of nitrogenous waste. A properly working filter, coupled with regular water changes and moderate feeding, should ensure ammonia levels are close to 0 parts per million and nitrate stays at a safe level (15 ppm or less).

We recommend: API Freshwater Aquarium Water Master Test Kit

Here’s why this fantastic product is a must-have for your Rainbow Shark care routine:

  • Comprehensive Testing: The kit includes tests for pH, high range pH, ammonia, nitrite, and nitrate, ensuring you’ve got all your bases covered.
  • Easy to Use: Clear instructions and color-coded charts make testing a breeze, even for beginners.
  • Accurate Results: Trustworthy and precise readings help you keep your water parameters in check and your Rainbow Shark happy.
  • Economical: With enough materials to perform over 800 tests, you’ll get your money’s worth for sure.
  • Peace of Mind: Regular testing with this kit helps you identify potential issues before they become serious problems, ensuring a healthy environment for your Rainbow Shark.

With the API Freshwater Aquarium Water Master Test Kit in your arsenal, you’ll be well on your way to maintaining the ideal water conditions for your Rainbow Shark’s long and happy life.


Tank Setup for Rainbow Shark Care

Rainbow Sharks are medium-sized community fish, growing up to 6 inches in length. They should therefore be kept in medium sized tanks (30 gallons) or larger. Since they are solitary bottom dwellers you shouldn’t keep them with others of their own kind but a few additional medium sized fish will provide the shark with dither activity.

Dither fish are open water swimmers that signal to shyer fish that the coast is clear and no predators are lurking. A solitary Rainbow Shark will spend all of its time hiding otherwise.

Tank Decorations

Alright, let’s talk tank decor. You want to create a cozy and comfortable environment for your Rainbow Shark, where they can swim, hide, and feel like the king or queen of their aquatic kingdom.

To achieve this, you’ll need to mix things up with various decorations that serve both aesthetic and functional purposes.

Here’s a list of tank decorations that you could try:

  • Plants: An underwater jungle is not just visually appealing but also provides hiding spots and stress relief for your Rainbow Shark.
  • Live Rock: A natural addition to your tank that adds some texture and helps maintain water quality.
  • Sandy Substrate: A soft and gentle surface for your Rainbow Shark to glide over while adding a pop of color to the tank.
  • Caves and Overhangs: Providing shelter and a sense of security, these structures will quickly become your Rainbow Shark’s favorite hangouts.
  • Corals and Artificial Reef Decorations: A little splash of marine life never hurt anyone, especially your Rainbow Shark. Just ensure these decorations are safe and won’t harm your fishy friend.

Remember: hardy plants like Java Moss are your new best friends, as they not only serve as fantastic hideouts but also help maintain water quality.


Compatible Tank Mates for Rainbow Shark Care

Rainbow Sharks are hardy and easy to care for but tank mates can be a constant problem in some settings. These fish are both semi-aggressive and territorial, meaning they will choose a space that no intruders are tolerated within.

WARNING: If you don’t cater to this need the shark will nip at just about any fish that hangs out around the bottom of the tank.

Assuming you decorate the tank to keep the shark from being too aggressive (see below), I suggest medium sized to large community fish. Other semi-aggressive fish are a good choice, including Tiger Barbs, Blue Gouramis, and larger Killifish. Rainbow Sharks can also live alongside aggressive fish like medium sized cichlids – Convict Cichlids are a good example.

Fast moving midwater to surface dwelling fish like Roseline Sharks, Giant Danios, and Bala Sharks are also excellent tank mates since they will rarely come into contact with one another. And even if they do, these fish are much faster than the Rainbow Shark.

Avoid keeping Rainbow Sharks with the majority of bottom dwelling fish like Corydoras and Plecostomus. Even if you give your Rainbow Shark a secure cave it will likely harass the poor, peaceful catfish to death since these fish have no concept of “territory” to avoid or defend.

Good Tank Mates for Rainbow Sharks Include:

  • Convict Cichlids, African Cichlids, and other Aggressive Fish
  • Gouramis, Tiger Barbs, Killifish, and other Semi-Aggressive Fish
  • Rainbowfish, Giant Danios, Bala Sharks, Roseline Sharks, and other fast Dither Fish

Rainbow Shark Diet

Like many Cyprinids (Barbs, Goldfish, Koi, Danios), Rainbow Sharks are true omnivores. This means that they need to feed on both plant and animal matter for optimal health. In nature these fish nibble on green algae and soft plants while hunting for worms, tiny shrimp, fish eggs, snails, insect larvae, and other treats along the bottom.

As a result, Rainbow Sharks are very unpicky when it comes to feeding. They will take both flakes and pellets with gusto. Just know that they have tiny mouths and can’t really swallow pellets easily unless you offer tiny pelles to an adult shark. Flakes are great even for adult sharks!

Supplement their prepared food with thawed frozen treats like brine shrimp and bloodworms. The carotenoids found in invertebrate based foods will also enhance the red and orange tones of their fins!

To give your Rainbow Shark the best dining experience…

We recommend: TetraColor Plus Tropical Flakes With Natural Color Enhancers

These flakes are packed with goodness and have some fantastic benefits:

  • Nutritious Formula: Providing a balanced diet with all the essential nutrients your Rainbow Shark needs to thrive.
  • Natural Color Enhancers: Boosting the vibrancy of your Rainbow Shark’s beautiful colors, making them stand out even more.
  • Easy to Digest: The flakes are designed to be easily consumed and digested by your fish, ensuring optimal nutrient absorption.
  • Suitable for All Life Stages: Perfect for both young and adult Rainbow Sharks, so you don’t have to worry about changing their diet as they grow.

Supplement their prepared food with thawed frozen treats like brine shrimp and bloodworms.

The carotenoids found in invertebrate-based foods will also enhance the red and orange tones of their fins!

How Often Should I Feed My Rainbow Shark?

Rainbow Sharks are bottom dwellers but they are fairly active, fast moving fish. They should be fed three times per day when young and at least twice per day as adults.

Even three times per day when fully grown won’t be an issue so long as the food portions aren’t too large.


Breeding Rainbow Sharks

Breeding Rainbow Sharks can be quite the challenge, even for experienced fish keepers. But don’t worry, we’re here to guide you through the process and help you understand what it takes to make baby Rainbow Sharks a reality in your aquarium.

Note: Breeding Rainbow Sharks is considered extremely difficult and is rarely successful in home aquariums. It’s important to keep in mind that attempting to breed these fish may lead to stress or aggression among tank mates. Always prioritize the health and well-being of your fish before attempting any breeding efforts.

How Do I Condition Rainbow Sharks to Spawn?

Unfortunately, breeding Rainbow Sharks is close to impossible in most aquariums. The fish are too intolerant of each other to pair off naturally. In the wild, Rainbow Sharks lead solitary lives until seasonal variations in water chemistry and temperature induce them to begin producing eggs and sperm.

At this stage, they then seek out one another and temporarily pair off, scattering their eggs in weedy plants, as all cyprinids do. Once they’ve spawned they then return to living solitary lives.

Rainbow Sharks are often captive-bred in huge ponds in Southeast Asia, where the weather and water conditions are exactly what they expect. Asian breeders often use hormonal treatments to more quickly induce the fish to spawn on a particular schedule.

The sizes of these ponds (thousands of gallons) also allows the sharks to keep any one fish from being bullied to death. Therefore, it’s next to impossible to breed these fish in a home aquarium.

How Can I Tell if a Rainbow Shark is Pregnant?

Assuming you’re certain that you have a female Rainbow Shark, she will become even more deep-bodied than normal. Her belly will swell with eggs and rather than attacking any males that approach, she will allow them to lead her towards a tangle of nearby plants to spawn.

Once the two embrace and release their eggs and sperm, she will appear much deflated and will return to her solitary ways.


Frequently Asked Questions for Rainbow Shark Care

Are Rainbow Sharks Good Beginner Fish?

Rainbow Sharks can be a fantastic choice for beginners, as long as you’re ready to dive into their specific care requirements. Remember, these fish need a decent-sized tank, proper water conditions, and a well-decorated environment to be happy.

Are Rainbow Sharks Aggressive?

Rainbow Sharks can be territorial fish, especially towards other bottom dwellers or similar-looking species like the red tail shark. They might show some aggression towards other rainbow sharks, so it’s best to keep a single rainbow shark in your tank.

However, when housed with the right tank mates, they tend to be peaceful fish, happily coexisting with other non-aggressive community members.

Are Rainbow Sharks Easy to Breed?

Nope, breeding Rainbow Sharks is far from easy. In fact, it’s considered nearly impossible in home aquariums. So, while you might be able to provide a top-notch home for your finned friend, breeding them is best left to the professionals in the aquarium trade.

What is Rainbow Shark Disease and How Can it be Prevented?

“Rainbow Shark Disease” isn’t a specific illness but rather a term that refers to various diseases that can affect these fish. To prevent issues, maintain optimal water conditions, provide a balanced diet, and keep an eye on your rainbow shark’s body for signs of illness.

NOTE: regular water changes and monitoring tank parameters are essential for keeping your fish healthy and disease-free.

What Does Rainbow Shark Eat and How Big Can It Get?

Rainbow Sharks are omnivorous, which means they eat both plant and animal matter. In the wild, they feed on a variety of small organisms including insects, crustaceans, and small fish. In captivity, their diet should consist of a mix of protein-rich foods and plant-based foods.

Some examples of foods that rainbow sharks eat are:

  • Algae wafers or flakes
  • Live or frozen foods such as brine shrimp, bloodworms, or daphnia
  • Sinking pellets or granules
  • Fresh or blanched vegetables such as lettuce, spinach, or zucchini

Rainbow Sharks do not grow abnormally large. They typically reach a maximum size of 5 to 6 inches depending on food availability and tank size. Although rainbow sharks are sold noticeably young at pet stores, they grow rapidly.

Normal Rainbow Sharks have a black or dark blue body with red or orange fins. They also have a distinctive stripe on their face that runs from the gill cover to the eye and mouth. They are sometimes confused with Red Tail Sharks, which have a deeper black body and a red tail only.

Can Rainbow Sharks Live in a Community Tank with Other Fish?

Absolutely! Rainbow Sharks can thrive in a community tank with other freshwater fish, as long as their tank mates are not too timid or similar-looking species.

Choose companions that dwell in different parts of the tank and avoid housing multiple Rainbow Sharks together to prevent territorial disputes.

How Often Should I Change the Water in my Rainbow Shark Fish Tank?

To keep your rainbow shark in tip-top shape, it’s crucial to change 25-30% of the water in their tank every two weeks. This helps maintain a stable environment and prevents the buildup of harmful substances.

What is the Difference Between Rainbow and Red-Tail Sharks?

Both of these fish are popular and can often be found in the same pet store! Red Tail Sharks are a deeper black in color and often have a white dot on the tip of their dorsal fin. And as their name suggests, only the tail is red, and usually a deeper red than that of Rainbow Sharks.

How Can I Sex Rainbow Sharks?

The best way to tell is by looking at how vivid their fin colors are: females tend to have duller fins than males. Female Rainbow Sharks are also deeper bodied, even if they aren’t carrying eggs.

Can I Keep Rainbow Sharks Together?

It’s not a good idea because they are very territorial and may fight to the death if there aren’t enough hiding spaces.

How Many Rainbow Sharks Should I Keep?

While it might be tempting to fill your tank with a school of these colorful fish, it’s best to stick with just one Rainbow Shark per tank. These fish are territorial and can become aggressive towards other Rainbow Sharks or similar-looking species.

Now that we’ve tackled those FAQs, here are some quick facts to amp up your Rainbow Shark knowledge:

  • Omnivorous Fish: Rainbow Sharks eat both plant and animal matter, happily chowing down on flakes, pellets, and the occasional invertebrate treat.
  • Red-Finned Shark: Don’t be fooled by the name; these beauties sport vibrant red finned shark-like tail fins that make them stand out in any tank.
  • True Sharks? Nah, despite their name, Rainbow Sharks aren’t true sharks, but they are some of the most popular freshwater fish in the hobby.
  • Young Sharks: When it comes to young Rainbow Sharks, aim to feed them three times per day for optimal growth and health.

And hey, if you’re ready to flaunt your own Rainbow Shark tank or aquarium like it’s the red carpet, come join our Facebook group with over 469k+ members and growing!



In conclusion, the Rainbow Shark Care Guide provides essential information on caring for both the normal and albino rainbow shark, popular freshwater fish known for their unique shark-like appearance and vibrant colors, including red finned sharks with the same red fins. These territorial, active fish can be aggressive, especially towards other rainbow sharks, making it important to choose suitable tank mates and maintain a larger tank size to minimize aggression.

A healthy diet for rainbow sharks consists of aquatic insects, algae wafers, and brine shrimp, while other aquarium fish, such as peaceful rainbow fish, can coexist in the same aquarium provided the tank is large enough. Other species, like the bala shark, silver shark, and red tailed shark, are also ray finned fish that share a similar body shape and behavior.

The aquarium hobby is growing in popularity, with pet stores offering a wide range of freshwater fish, including the juvenile rainbow shark and its many color variations, such as the ruby shark with its dark blue body and orange fins. However, it’s crucial to ensure a secure aquarium lid and a well-maintained environment to support the health and well-being of these fascinating creatures.

By understanding the natural habitat and behavioral tendencies of the rainbow shark, such as their territorial nature and potential aggression towards other fish, aquarium enthusiasts can better manage their interactions with other species in the same tank. Offering proper tank size and hiding spots, along with a diet rich in brine shrimp and other suitable foods, helps ensure a thriving and enjoyable experience for both the rainbow sharks and all the other fish sharing their aquatic home.


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