Rainbow Shark: Care, Size, Lifespan, Diet & More

Rainbow Shark(Epalzeorhynchos frenatum) is a beautiful shark-looking species of freshwater fish. This fish is highly sought after for its beautiful red fins and dark body. If you’re thinking about adding a Rainbow Shark to your aquarium, there are a few things you should know. These fish are semi-aggressive, so they may not do well with other peaceful community fish. They also need a lot of space to swim and plenty of hiding places.

In this article, you will learn how to properly care for a Rainbow Shark as well as other relevant information that will help you take good care of these misunderstood species.

Species Profile & Overview

Rainbow Shark fish are found in freshwater rivers and streams in Southeast Asia. They are often found in Indonesia, Thailand, Laos, Myanmar, and Malaysia. 

These fish belong to the Cyprinidae family of fish that are commonly known as carp or minnow fish. The Rainbow shark is known by a couple of different names like Ruby Shark, Red-fin Shark, Green Fringelip Labeo, and whitetail shark minnow.

In the wild, these fish prefer areas with fast-moving water with plenty of hiding places. Rocks, logs, and aquatic plants provide cover for these shy fish. Their dark color lets them hide in the shades without being seen. 

The Rainbow Shark is a beautiful fish that has a jet-black body color. It has beautiful reddish-orange fins that create a beautiful contrast with its black body. However, there are a few other color mutations available that make these fish a popular choice for aquariums.

Despite the name, Rainbow Shark is not a type of shark and they can’t live in saltwater. These carp/minnow fish are called “Sharks” because of their appearance which resembles a saltwater shark. They are typically found in fast-moving waters, and they prefer to stay near the bottom of the tank.

These fish are known for being semi-aggressive, and they may fight with other fish if they feel threatened. But they can be a beautiful addition to any freshwater aquarium if the right conditions are set. The majority of the time their aggression is due to an overcrowded tank.

Overall, these small and shark-looking fish are easy to care for and are a great choice for aquarists who want to add some unique-looking fish to their tank.


Rainbow Shark
Rainbow Shark

The rainbow shark is known for its brightly colored fins and dark-colored body. This makes them super popular fish in the aquarium hobby. They are available in many vibrant body colors, which can include Black, Albino, Yellow, Blue, and Purple. 

The fins are usually bright orange but some species might have some or none of their fins colored black. In fact, the famous Red Tail Shark is the same species as Rainbow Shark but marketed as different species of fish. The Red Tail Shark is a variant of Rainbow Sharks that is developed to only have its tail in red color.  

These fish have slender bodies that are torpedo-shaped, with a long tail fin. The coloration of rainbow sharks is variable, but they typically have a dark gray or black body with bright red, orange, or yellow fins.

The eyes are small and set close together, and the mouth is located at the tip of the snout. The eyes are very large in comparison to their small head. But they are perfectly placed to help the fish see a wide area around them.

The pectoral fins are long and thin, and the pelvic fins are shorter and thicker. The caudal fin is forked, with the upper lobe being longer than the lower lobe in some specimens. The fins on a Rainbow Shark’s body are arranged in a way that makes the shark look very sleek and streamlined.

Rainbow Shark fish is a popular choice for aquariums because of their vibrant colors and their resemblance to a saltwater shark. Yet they stay small and are not aggressive predatory fish. They are also known for being hardy fish that can thrive in a variety of water conditions. Rainbow Sharks are active swimmers and will add interest and movement to your aquarium.

Note: Males are usually thinner and can have black lines on their tail fins.

Adult Size

Rainbow Shark fish are a beautiful addition to any aquarium. They are relatively small fish, only reaching about 6 inches in length. Their small size but vibrant coloration will surely catch the eye of any onlooker. 

Despite their somewhat medium size, Rainbow Sharks can get along well with other tank mates when the aquarium is not overcrowded. They are also active swimmers and will often be seen cruising around the tank in search of food.


Rainbow Shark fish have a lifespan of between 4 and 6 years. Diet and water quality can play a significant role in determining the lifespan of these fish. Poor diet and water quality often lead to a shorter lifespan.

Aquarium maintenance is vital to the health of your shark fish. Over time, debris and algae can build up in the tank, which can lead to poor water quality and potentially harm your fish. A regular cleaning schedule will help to keep the tank clean and the water quality high, which will create a healthier environment for your fish.

Behavior & Temperament

Rainbow sharks are semi-aggressive and territorial fish that will attack other fish in their territory. However, when the bottom of the tank is not crowded, they will often remain peaceful. 

If other bottom-dwelling fish are in the tank, this fish may become territorial. Rainbow Sharks are active swimmers and will constantly swim around. Having other bottom dweller fish in a small tank can cause issues as they might fight over territory with each other.

One way to prevent aggressive or territorial behaviors in Rainbow Shark is to keep them in a tank that is at least 50 gallons. This will give them enough room to swim and explore without feeling cramped and stressed. 

Another way to prevent aggression is to keep only one Rainbow Shark per tank. If more than one Rainbow Shark is kept in a tank, they may become aggressive toward each other.

When keeping Rainbow Sharks in a group it is important to make sure your tank can house all of them. The rule of thumb for the number of rainbows you can keep in a tank is one rainbow shark per 2 square feet of the aquarium. 

It is recommended to keep them in a tank with other fish that are of similar size and temperament. Rainbow Shark fish are active swimmers and will often swim in groups. They prefer to have plenty of space to swim and will often hide among plants and rocks.

Rainbow Shark Care

Rainbow Shark is a good beginner fish because they are easy to care for. They are peaceful fish but may become territorial with other Rainbow Shark fish or similar-looking fish. So it is important to set up their tanks the right way to prevent territorial behaviors.

Rainbow Shark fish are also adaptable to a wide range of water conditions and are considered to be hardy fish. They are able to tolerate a wide range of temperatures and can even live in brackish water. These fish are also known to be able to adapt to different types of food, so they are not picky eaters.

To create the ideal environment for your Rainbow Shark, we recommend following the recommendations made in the next few sections.

Tank Size

A Rainbow Shark fish needs a minimum tank size of at least 50 gallons. They can share a tank of this size with up to 2 other Rainbow Shark fish. If you want to have more than that then you need to make sure your tank has 2 SQF of bottom area for each fish. 

When a tank has a lot of hiding spots separate from each other, these fish will not show territorial behaviors even if kept in larger numbers in a smaller aquarium. You will need to make sure the water quality is high at all times. So never overcrowd a tank even if your tank has room to add fish. 

Rainbow Shark fish are a great addition to any large aquarium. They are very active and playful, and their bright colors add a splash of color to any tank. Rainbow Shark fish are also very hardy and can live for many years with proper care. 

What To Put In A Rainbow Shark Tank

Aquarium decoration for Rainbow Shark fish should be done in a way that suits their natural habitat. This means creating an aquascape with plenty of hiding places to hide but enough open bottom areas for swimming and exploring.

Driftwood, live plants, and rocks can all be used to create a natural-looking aquarium that Rainbow Sharks will feel comfortable in. When choosing plants, be sure to select ones that are tough and can withstand some aggression from the sharks.

There are many benefits to using natural decorations like rocks and driftwood in an aquarium. They can help the tank to look more beautiful and natural, and can also provide a hiding place for fish and other aquatic creatures. Natural decorations can also help to keep the water quality in the aquarium high by providing a place for beneficial bacteria to grow.

A Rainbow Shark aquarium should have a substrate that is dark in color. This will help the Rainbow Shark to feel more comfortable and feel safe. But unfortunately, it’s hard to find this fish as it will blend in with the black substrate. 

The substrate should be fine sand so these fish do not harm themselves when swiftly swimming on it. The bottom of the tank is where they are mostly staying so it has to be comfy for them. 

We can not stress enough about having live plants in your tanks. There are many benefits of having live plants in an aquarium. These plants can make a tank more balanced and healthy for Rainbow Shark fish. 

Live plants help to oxygenate the water and provide a natural source of food and shelter for the fish. They also help to keep the water clean and clear by filtering out excess nutrients and waste products. A well-planted tank is also more aesthetically pleasing than a bare one.

Some of the best plants for a Rainbow Shark tank are Bucephalandra, Anubias, Java Fern, and Anacharis. You can also keep different types of floating plants or other hardy types of plants with these fish.  

Note: These fish are known to eat fragile and soft types of plants so make sure you pick hardy plants that have tough leaves. 

Rainbow Shark
Rainbow Shark

Light Requirements

Good light is necessary for an aquarium because it can help make the rainbow shark look more beautiful. However, rainbow sharks themselves do not need any specialist lighting. These fish are nocturnal and as long as they get a hiding spot during the day, they will be okay with any lighting conditions.

If you are looking for an aquarium light, it is important to find one that is the right size and type for your plants rather than the fish. The best type of light for an aquarium is a full-spectrum LED light. These lights provide natural-looking daylight that can help the plants to grow and bring out the colors of your fish.

Your light should be on a timer so it turns on and off at specific hours. This will replicate the day and night hours for the fish and plants and lets them adjust to a set day and night time to function properly.

Water Parameters

Rainbow Shark fish are a very adaptable species of species and can adjust to a wide range of water parameters. Making them a good choice for many different types of aquariums. It is important to match the water parameters of your aquarium to the natural habitat of this species to provide them with the best possible life.

A Rainbow Shark is a tropical fish that requires a tank with warmer water. They also require a moderate to high water current. To create a moderate water current in an aquarium, you can use one or more powerheads. 

Considering all these key points, you should aim to keep Rainbow sharks in the following range of parameters: 

  • Temperature: 75 – 81 Degrees Fahrenheit 
  • PH: 6.0 – 8.0
  • TDS: 80 – 250 PPM

Filtration System

Filtration is an important aspect of keeping a Rainbow Shark healthy and happy. A good filtration system will help to keep the water clean and free of debris, as well as provide a place for the fish to hide and feel secure. A Rainbow Shark’s tank should be at least 50 gallons, and the filter should be able to handle at least 2 times the volume of the tank.

Aquarium filters play an important role in keeping the tank clean and the water quality high. A good filter should be able to filter the water mechanically, chemically, and biologically. Fortunately, there are many different types and sizes of quality filters that provide all 3 types of filtrations. We recommend having a canister filter as they are the most stable type of filter you can buy.

Common Diseases and Prevention

There are many different diseases that can affect Rainbow Shark fish. Each one can have a different effect on the fish’s health and appearance. Some of the more common diseases include bacterial infections, fungal infections, and parasites. These diseases can cause sharks to look ugly and even die if they are not treated properly.

The best way to prevent diseases is to maintain a clean and healthy aquarium. This includes regular water changes, vacuuming the gravel, and cleaning the filter. It is also important to feed your fish a nutritious diet and to avoid overfeeding. 

Most aquarium diseases develop naturally when water quality is low. However, there are times when some diseases get introduced to your tank. When you buy fish, plants, or invertebrates from stores you must always quarantine them for a long period of time before adding them to your Rainbow Shark tank. 

Doing this will prevent diseases from spreading into your aquarium system. If your fish does become sick, it is important to separate and quarantine the sick fish immediately and to consult a veterinarian who specializes in fish health.

Diet and Feeding Requirements

Rainbow sharks are omnivore species but they prefer vegetarian foods more. They have been known to eat small invertebrates and insect larvae but this is not a common occurrence. They mostly prefer to eat algae and plant matter. 

In an aquarium environment, there are a few foods that are good for Rainbow Sharks. One is dry foods like flakes and pellets. Another is live or frozen food, such as shrimp meals, brine shrimp, or bloodworms.

Dry, commercially made aquarium fish foods are not very nutritious for Rainbow Sharks. But they are the easiest method of feeding. Because these fish stay at the bottom of the tank you must buy sinking types of foods so your fish can eat.

Dry foods should be fed on a regular basis and frozen fish foods should be given once or twice per week. When mixing different types of foods, you are making sure your fish receives all the nutrients it needs. As a result, your fish will live a healthier and longer life. 

Overfeeding is unhealthy for rainbows and the aquarium environment. When fish are overfed, they produce too much waste, which can pollute the water and make it unhealthy for the fish. Overfeeding can also cause fish to become obese, which can lead to health problems.

Tank Mates

Rainbow Shark fish are generally peaceful towards other tank mates but can be territorial with fish of the same species. They are more likely to display aggression in smaller tanks, and the aggression increases as the tank size decreases. 

In larger tanks, they are less likely to be aggressive and more likely to hide. This fish should be kept with similar-sized fish that are not aggressive. It is also best to not add any other bottom-dweller fish if the tank is small. 

Here are a few of the species you can keep with your Rainbow Shark:

Rainbow Shark
Rainbow Shark


The Rainbow Shark is a beautiful and unique fish that can make a great addition to any aquarium. They are relatively easy to care for and can be peaceful community fish when kept with other peaceful species. However, they can also be territorial and aggressive towards other fish, so it is important to make sure your tank can house them before adding one to your tank. Rainbow Sharks are fun and interesting fish to watch, and they will surely add some color and personality to your aquarium.