Rainbow Shark: The complete Care Guide

Rainbow Sharks, also known as RedFin Sharks or Ruby Sharks, are small tropical freshwater fish native to Thailand. They are known for their variant red fins and being territorial.

Care Level:Easy/Moderate.
Color Form:Gray, Red.
Lifespan:5-8 Years.
Size:Up To 6 inches.
Minimum Tank Size:50 Gallons
Tank Set-Up:Tropical Freshwater: Rocks, Caves, or plants.
Compatibility:Moderate, get along with many other freshwater fish.
Rainbow Shark: The complete Care Guide
Rainbow Shark

Overview of Rainbow Shark

The Rainbow Shark is a tropical freshwater fish. It is suitable for those who have one or two years of experience in aquariums.

This Fish is known for its territorial nature and bright vibrant red fins. They gain the name Rainbow due to their upright dorsal fin which gave them the appearance of a shark.

The Rainbow Shark can grow up to 6 inches and have a lifespan of 5-8 years. If you want to keep Rainbow Sharks in your aquarium, You should make sure your aquarium has plenty of hiding places for them as this helps to reduce their territorial behavior.


The Rainbow Shark is a dark gray fish with vibrant red/orange fins. They have a long, flat stomach with a pointed snout and an upright dorsal fin.

This is the fin that gives them the appearance of a shark. The Rainbow Shark is a small fish that you should expect to grow up to around 6 inches when fully matured.

It is not possible to identify their gender while they are young. You have to wait until they are sexually mature.

Once sexually matured females have thicker bodies, and males will develop small black lines on the tail fin also males are thinner. They will generally have brighter colorations.

Typical Behavior of Rainbow Shark

The Rainbow Shark is a bottom to mid-level dweller. It is territorial fish that can cause certain behavioral problems like aggression and dominance.

They are peaceful to their kind in the wild but in the tank, they are known to be aggressive.

Especially when you keep two or more same Rainbow shark fish or small fish in the same tank. Due to their aggressive behavior, it is not recommended to the new aquarist.

Tank Requirements for Rainbow Shark

Tank Size

The minimum tank size for this fish is 50 gallons. The size will increases if you add more fish to the tank.

You must not consider a smaller tank for this fish. The tank wide should be at least 20 inches for one fish.

This will give the fish plenty of space to swing around. If your tank has less horizontal space then the fish will be more aggressive.

Water Condition

With Rainbow Shark, you must keep the pH level stable. A sudden change in pH level can make this fish more aggressive than usual.

The pH level should be 6.5 to 7.5. The temperature should be between 75-81ºf. Maintain the water hardness of 5 to 11 DH. The light level should be at a medium level and the water flow should be moderate.

Feeding Requirement of Rainbow Shark

It is an omnivore so it will it both plants as well as meat. In their natural environment, they eat algae, insect larvae, and bits of meat such as zooplankton. In the aquarium, they will also eat algae from the bottom of the tank.

They will also eat flack food, frozen food, pellets, vegetables, and live food. It is a good exercise to give them a variety of food. Like what they get in the wild for instance algae, insect larvae, and zooplankton.

You can also add some chopped Cucumber, raw Peas, and pieces of Spinach as well. Feeding should be at regular intervals approximately two or three times each day.

Do not overfeed your fish. Give them what they can eat in a single meal. Or it will impact your Nitrogen cycle.

It is especially important to pay attention to their diet while it is still juvenile. Feeding your young shark a variety of foods to make sure that the growth and color.

Fish that do not get enough variety of food their growth may be stunted and fins that are not bright as they should be.

Suitable Tankmates for Rainbow Shark

If you want a clam community tank then Rainbow Shark is not for you. They can get along with many other freshwater fish species. Being territorial fish can be overwhelming to nonaggressive fish.

It is a bottom-dwelling fish, so avoid another bottom-dwelling fish in the same tank. Having more bottom dwellers in the same tank as Rainbow Shark can cause more problems.

A shortlist that should not be placed in the same tank as Rainbow Shark

  • Bala Sharks.
  • Red Tails Sharks.
  • Cichlids.
  • Catfish.

Instead of bottom-dwelling fish go for middle and surface-dwelling fish. Like

  • Gouramis.
  • Rasboras.
  • Danios.
  • Rainbowfish.

Due to their semi-aggressive nature, there is always some risk anytime you place other fish in the tank with the rainbow shark. To avoid this place your other fish first and place the rainbow shark last.

Also, give them plenty of plants and hiding space. That will make them less aggressive.

This will keep everyone feeling safe. Sometimes they can be more aggressive toward one another as well. This is maybe because of their dominant behavior. One is trying to assert dominance over the other.

Try to put at least five Rainbow Sharks together in the same tank. If you want to own multiple ones. This will reduce the dominant behavior a little less.

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Hey, I am Shuvradeb Biswas a content writer. Fishkeeping is my hobby. There are many problems I faced during my first fishkeeping. So, I made the KeepingWorld.com blog to help new fishkeepers.

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