The 15 Best Tank Mates to Pair With Rainbow Sharks

A black rainbow shark with a red tail eats from the bottom of the aquarium

Written by Lev Baker

Updated: November 1, 2023

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Here are the 15 best tank mates for Rainbow sharks.

Don’t worry; rainbow sharks are not true sharks – they are just named after their shark-like appearance due to their red dorsal fin. Scientifically classified as Epalzeorhynchos frenatum, rainbow sharks are freshwater fish originating from Southeast Asia, specifically Myanmar, Thailand, Laos, and Malaysia. They typically reach a size of 4 to 6 inches and have an average lifespan of 5 to 8 years.

Though rainbow sharks are beautiful to keep in any aquarium due to their striking color and active nature, they fall into the semi-aggressive category and might display aggression towards other fish in certain situations. To ensure proper care, they require adequate space and hiding spaces in your tank. The ideal rainbow shark tank size is 50 to 55 gallons at minimum, and they do best in water between 6.5 and 7.5 pH. Furthermore, the water temperature is best kept between 72 and 81 degrees Fahrenheit.

Rainbow sharks are better suited for experienced aquarium keepers rather than beginners due to their territorial behavior. However, if you are passionate about them, this article will help you understand the 15 suitable tank mates for rainbow sharks, and offer insights into their care and requirements for a harmonious and enjoyable aquarium setup. So, without further ado, let’s dive in!

1. Tiger Barb (Puntius tetrazona)

A popular aquarium fish, the


barb is a great tank mate for rainbow sharks.

©Faucon, CC BY-SA 2.5, via Wikimedia Commons – Original / License

Tiger barbs are some of the most popular aquarium fish, and caring for them is relatively simple. They are vibrant and engaging fish, known for their distinctive black stripes set against a lively orange or gold body. These barbs originated from Southeast Asia. These fish are compact, typically reaching a size of 2 to 4 inches. Tiger barbs prefer well-maintained water with temperatures between 72 to 82°F and a pH level of 6 to 8, making them compatible with rainbow sharks. For a group of six or more tiger barbs, a larger tank of 40 gallons or more is recommended.

Tiger barbs can make excellent companions for rainbow sharks as they are quite active and move around a lot. Tiger barbs also prefer to be in the middle level of the tank, thus leaving rainbow sharks their territory at the lower level.

2. Zebra Danio (Danio rerio)

A macro shot of a zebra danio tropical fish.

Known for their zebra-like stripes, zebra danios are peaceful fish.

©Ian Grainger/

Zebra danios, originally from South Asia, are charming fish distinguished by their striking zebra-like stripes. Their petite size, typically up to 2 inches, makes them an ideal choice to pair with rainbow sharks, as they are small, peaceful, and swift enough to swim away if needed. Zebra danios are schooling fish, so keep them in groups of at least five, thus a tank size of around 10 to 15 gallons can suffice.They should also have well-maintained water with temperatures ranging from 65 to 77°F and a pH level of 6.5 to 7.4.

3. Harlequin Rasbora (Trigonostigma heteromorpha)

Harlequin rasbora (Trigonostigma heteromorpha) on a fish tank

With their beautiful metallic color, harlequin rasboras are calm in nature.

©Joan Carles Juarez/

Harlequin rasboras, originating from Southeast Asia, have a beautiful metallic color and are easy to care for. They are one of the best tank mates to pair with rainbow sharks as they are peaceful and tend to stay in the top to middle sections of the tank, allowing rainbow sharks their space.

This species typically reaches about 2 inches in size, making them a good tank mate as they are large enough not to be eaten nor attacked. Moreover, their calm demeanor complements the rainbow sharks’ energy, creating a balanced environment. Their swift movements and schooling behavior further reduce the risk of aggression. Taking care of them is simple: they prefer well-maintained water around 72 to 82°F and a pH of 6 to 7.8. 

4. Congo Tetra (Phenacogrammus interruptus)


Growing relatively large in size, the Congo tetra is a good tank mate for rainbow sharks.


The Congo tetra, native to Central Africa, has vibrant iridescent colors ranging from blue to red. These fish are charming and suit the rainbow shark as tank mates as they grow relatively larger in size compared to other fishes, thus reducing the chance of being preyed on or nipped on. Congo tetras can grow to around 3 to 4 inches, and they are calm in nature, which makes them great tank mates for the semi-aggressive rainbow sharks. Furthermore, they love to dwell in the middle to top sections of the tank, allowing them to live peacefully with the bottom-dwelling rainbow shark.

When setting up the tank for Congo tetras, the water temperature should be between 73 to 82°F and a pH of 6 to 7.5. Congo tetras also like to be in small groups, so a larger tank of 40 gallons or more is best if you intend to keep a group of six or more.

5. Blue Gourami (Trichogaster trichopterus)

Male blue gourami (Trichopodus trichopterus) in an aquarium, close-up

Due to their calm nature, blue gouramis can make excellent tank mates for rainbow sharks.


The blue gouramis are also one of the best tank mates for rainbow sharks when adequate tank space is provided, as these fish can occupy all sections of the tank. So, if needed, they can give space for fish like rainbow sharks when needed. Furthermore, blue gouramis have a calm demeanor that complements the energy of rainbow sharks, thus creating a balanced tank dynamic. These fish originated from Southeast Asia and are captivating fishes renowned for their shining blue scales with intricate patterns.

For a single blue gourami, opt for a tank size of at least 30 gallons. These fish can reach sizes of up to 4 to 6 inches in length, so providing enough swimming space is important. They also prefer well-maintained water around 72 to 82°F and a pH of 6 to 8.

6. White Cloud Mountain Minnow (Tanichthys albonubes)

Aquarium fish White Cloud Mountain minnow swimming against soft green plants background. Detailed fish pattern. macro nature concept. soft focus photo.

A popular aquarium fish, the white cloud mountain minnow is a schooling fish.


White cloud mountain minnows are dainty and elegant fish. They are another excellent tank mate for rainbow sharks due to their peaceful nature. These fish come from China and thrive in well-maintained water of around 60 to 72°F and a pH of 6 to 8.5. They also require ample hiding places and plenty of vegetation to imitate a natural habitat. For a small group, a tank size of around 10 to 20 gallons is suitable.

White cloud mountain minnows usually grow to around 1.5 to 2 inches. Due to their small size, they may be threatened by rainbow sharks. But they still make good tank mates because they mostly stay in the upper to middle parts of the tank, where it is safe. White cloud mountain minnows are also schooling fish – this behavior can act as a defense against potential predators.

7. Bristlenose Pleco (Ancistrus cirrhosus)

Bristlenose Plecos, freshwater algae eater fish.

If you want an interesting-looking fish, go for the bristlenose pleco.


Bristlenose plecos are fish with a flat body and bushy tentacles, and prefer to be at the bottom of the tank – just like the rainbow shark. They also help to keep your aquarium clean by eating algae. Not only are these fish calm and make good tank mates for your rainbow sharks, but their larger size also makes them less likely to be bullied by the rainbow shark.

Bristlenose plecos originated from South America and are one of the most popular aquarium fish. They typically grow to around 4 to 6 inches, and prefer well-filtered water around 72 to 82°F with a pH of 5.8 to 7.8. As they grow quite large, it is best to keep a single bristlenose pleco with a tank size of around 20 to 30 gallons. With adequate tank space, both species can cohabit harmoniously.

8. Dwarf Neon Rainbowfish (Melanotaenia praecox)

Neon dwarf rainbowfish

A social fish, the dwarf neon rainbowfish is best kept in groups of at least five.


The dwarf neon rainbowfish is an active and social fish that can get along well with various other fishes. Their iridescent blue and orange hues are captivating and add a delightful touch to aquariums. These fish typically reach about 2.5 to 3 inches long and are schooling fish, so it’s best to keep them in groups of at least 5.

For a small group of these fish, a tank size of around 20 to 30 gallons would be appropriate. Dwarf neon rainbowfish are best kept in a water temperature of around 72 to 80°F and a pH of 6 to 7.5. These rainbowfish make great tank mates for rainbow sharks, as they are not territorial and are peaceful creatures. And since they are relatively small, they aren’t likely to antagonize or worry the rainbow shark.

9. Rummy Nose Tetra (Hemigrammus rhodostomus)

A macro shot of a rummy-nose tetra tropical fish.

With its vibrant red head, the rummy nose tetra stands out.

©Ian Grainger/

The rummy nose tetra, originating from South America, is an interesting fish known for its distinctive appearance. It has a vibrant red head and silver body, and usually grows to around 1.5 to 2 inches. These tetras have a peaceful nature and are ideal companions for rainbow sharks. Not only does their calm demeanor help balance out the energy of rainbow sharks, but also their schooling behavior and swift movements make them less likely to be targeted by the rainbow shark. To keep rummy nose tetra, make sure to get a minimum tank size of 20 gallons. Water should be kept at around 72 to 82°F with a pH of 5.5 to 7.

10. Hillstream Loach (Sewellia lineolata)

Gold Ring Butterfly Sucker, Reticulated Hillstream Loach, Tiger Hillstream Loach (Sewellia lineolata, Balitora lineolata)

Another good tank mate for the rainbow shark is the hillstream loach.

©Pavaphon Supanantananont/

The hillstream loach, also known as the butterfly loach, originates from fast-flowing hillstream waters in parts of Southeast Asia. These unique fish have flattened bodies and are adapted to cling to rocks and navigate strong currents. In an aquarium setting, they are bottom dwellers. Therefore, it is important to have a large tank for the loach and rainbow shark to peacefully cohabitate and reduce competition for space.

Hillstream loaches can grow to about 2 to 3 inches in size, therefore requiring a tank capacity of a minimum of 50 gallons. They also thrive in cooler waters with temperatures ranging from 68 to 75°F and pH levels around 6.5 to 7.8. What’s special about the hillstream loaches is their striking appearance with intricate patterns and their ability to withstand a wide range of environments. With their sucker-like mouths, they are able to graze on algae and microorganisms and can even clean your tank! Overall, these loaches make ideal tank mates for rainbow sharks due to their relaxed nature. 

11. Angelfish (Pterophyllum scalare)

portrait of a zebra Angelfish in tank fish with blurred background (Pterophyllum scalare)

Popular aquarium fish, angelfish are territorial.

©Joan Carles Juarez/

Angelfish come from South America’s Amazon River basin and are captivating freshwater fish admired for their graceful appearance and distinctive triangular shape. They can grow to about 6 to 12 inches long (depending on the type) and require a minimum tank size of 30 gallons. Angelfish prefer warm water around 75 to 86°F and a pH of 6.5 to 7.8.

Angelfish are well-suited as tank mates for rainbow sharks, but keep in mind that both types of fish are territorial, so they may nip at each other from time to time.

12. Scissortail Rasbora (Rasbora trilineata)

Scissortail Rasbora (Three Lined Rasbora) is swimming in freshwater aquarium. Rasbora trilineata is a tropical freshwater aquarium fish native to swamps in Southeast Asia.

Named for their tails, scissortail rasboras can grow up to 4 inches.

©Arunee Rodloy/

Scissortail rasboras have sleek bodies and tail fins that look like scissors, hence their name. They usually grow to about 3 to 4 inches and thrive in tanks that are a minimum of 20 gallons. These fish also prefer slightly acidic to neutral water with a temperature of 72 to 82°F.

Scissortail rasboras are ideal tank mates for rainbow sharks as they tend to swim around the middle of the tank, so they’ll be out of reach. Conversely, rainbow sharks prefer the bottom. And since rainbow sharks require a minimum tank size of 50 to 55 gallons, the scissortail rasboras will have more than enough space to swim around out of reach.

13. Honey Gourami (Trichogaster chuna)

Interestingly, honey gouramis can create bubble nests.

©Przemek Iciak/

Honey gouramis are small and charming golden fish that are popular choices for aquariums. When their scales are captured in the sunlight, they give off a beautiful golden shimmer. Honey gouramis can grow about 2 to 3 inches long and can thrive well in a 10-gallon tank. They like warm water around 71 to 82°F and a pH of 6 to 7. Honey gouramis are famously known to build bubble nests, which makes them very entertaining to watch. These nests are an interesting mixture of air bubbles, saliva, and other types of adhesive mucus, holding everything together.

Honey gouramis are very peaceful and make good tank mates for rainbow sharks. Moreover, they dwell in the upper section of the tank, so the tank won’t be crowded, and the rainbow sharks will still have their much-needed space.

14. Black Ruby Barb (Pethia nigrofasciata)

Aquarium fish.The black ruby barb (Pethia nigrofasciata) or purplehead barb is a tropical cyprinid fish endemic to Sri Lanka where it occurs in forested streams.

These fish prefer the middle of the tank, leaving the bottom for rainbow sharks.

©Karel Zahradka/

The black ruby barb is a stunning fish known for its captivating black-red hue, hence its name, that glistens in the light. Growing to around 2 to 3 inches in length, they thrive in a minimum tank size of 20 to 30 gallons, so the 50 to 55 gallons needed for rainbow sharks will be more than enough space! Furthermore, these barbs prefer slightly acidic to neutral water, with a temperature of 72 to 79°F. Their remarkable coloration and lively nature make them a standout choice.

Besides the tank compatibility, black ruby barbs also make great companions for rainbow sharks as they will leave the bottom of the tank for rainbow sharks to swim around in. Black ruby barbs instead prefer to inhabit the middle of the tank, helping to create a balanced and visually appealing aquarium setting.

15. Black Skirt Tetra (Gymnocorymbus ternetzi)


The final tank mate for the rainbow shark is the black skirt tetra.

© Carlos Juarez Jaramillo

The black skirt tetra is one of those aquarium fish that get along with almost anything – including rainbow sharks. Plus, they can add a visual delight to your aquarium. These tetras have a sleek body adorned with flowing fins. Averaging around 2.5 inches in size, these fish prefer a minimum tank size of 20 gallons, a water temperature of 72 to 82°F, and slightly acidic to neutral pH levels.

Black skirt tetras can be a bit aggressive towards long-finned fish, but are generally friendly with many other semi-aggressive types, including rainbow sharks. Their preference for the upper and middle levels of the aquarium and their love for plants and hiding spots further make them great companions for rainbow sharks.

Summary of Ideal Tank Mates to Pair With Rainbow Sharks

NumberTank MateScientific Name
1Tiger barbPuntius tetrazona
2Zebra danioDanio rerio
3Harlequin rasboraTrigonostigma heteromorpha
4Congo tetraPhenacogrammus interruptus
5Blue gouramiTrichogaster trichopterus 
6White cloud mountain minnowTanichthys albonubes
7Bristlenose plecoAncistrus cirrhosus
8Dwarf neon rainbowfishMelanotaenia praecox
9Rummy nose tetraHemigrammus rhodostomus
10Hillstream loachSewellia lineolata
11AngelfishPterophyllum scalare
12Scissortail rasboraRasbora trilineata
13Honey gouramiTrichogaster chuna
14Black ruby barbPethia nigrofasciata
15Black skirt tetraGymnocorymbus ternetzi

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About the Author

Lev is a writer at AZ Animals who primarily covers topics on animals, geography, and plants. He has been writing for more than 4 years and loves researching topics and learning new things. His three biggest loves in the world are music, travel, and animals. He has his diving license and loves sea creatures. His favorite animal in the world is the manta ray.

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