Rainbow Shark – The Complete Care Guide of the Rageful Pet

Rainbow Shark in its natural habitat
By Garrison Hickles Updated

Do you have a fondness and hobby to add a colorful fish like multi-shaded Rainbow Shark in the fish tank of your house or office? Before breeding such bright pet fish, get a few interesting ideas and vital information about this particular species which will help you take care of your tiny companion.

Quick Details on Rainbow Shark

You may have a quick look on the table to get familiar with the precise details for the newest member of your aquarium, Rainbow Shark before including it in your pet fish family.

Scientific NameEpalzeorhynchos bicolor
OriginSouth Asia (Thailand)
Life-Span5-8 Years
Color FormGray, Red, Black, White, Dark Blue
Size               6-7” (15 cm)
CompatibilityFamiliar with Calm Fish Companions
Tank Size50-60 Galloons
Care LevelModerate


Among various freshwater shark fish, a bright little Rainbow Shark is chosen by the fish owners because of its lively color that brings a gleam to the fish tank. People also know this South Asian water-species by other names like Red-Fin Shark, Red-Tail Sharkminnow or Rainbow Sharkminnow. Generally, the price of Rainbow Shark is $3. However, the range may vary for different countries and states. While storing these fish, just plan to bring a huge-spaced aquarium, so that they can swim and breathe properly in the aerated water.

Origin of Rainbow Shark Fish

Generally, the main origin of this bright-colored Rainbow Shark is the warm stream of Chao Phraya river in Thailand in South Asia. These Shark fish flow swiftly in the terrestrial tropical freshwater stream of Indo-China Basin, and from that place, fish-keepers collect the species and sell it.

Tank Requirements for Rainbow Shark

The active and fast swimming Rainbow Shark fish needs at least 50-60 gallons area in a fish tank. Moreover, the fish tank should have horizontal space, otherwise, these wild and free-natured fish will feel suffocated in your aquarium which is the prime source of its anxiety and frustration as per animal psychologist.

Tank Size

A minimum 50-gallon aquarium is required for the 7” (15 cm) Rainbow Shark because it has a tendency to jump and come out from the tank, so experts suggest keeping this fish in a spacious tank.


Surround the living place of Rainbow Shark with small caves, rocks, and greenery, so that it doesn’t feel stressed because of the isolated and less ornamental environment in the tank. Don’t keep sharp gravels because the sharp-edged pebbles may injure them.


Fix a normal LED light on the tank ceiling of Rainbow Shark because this fish does not need any special lighting for its tank.


Native to the Indochina River Basin, Rainbow Shark prefers living in high-flowing water. So, add a horizontal filtration system in the tank of your favorite pet fish in order to keep the flow of the water high.

Water Type for Rainbow Shark

While keeping water in the tank, you need to follow some major requirements so that your little swimmer buddy stays comfortably in the fish tank.


The temperature of the water should be 80°F (26°C).

pH Level

The pH range of the water should be 6.0 to 8.0.


The hardness of the water should be 5 to 11 dGH.

Cleaning Method

Human beings like living in a clean and hygienic condition, so why don’t you give the same amenity to your pet fish? If you are a fish hobbyist then you should learn how to clean the tank of a pet Rainbow Shark. Just buy a liquid soap and use a soft brush or sponge to clean the entire objects, walls, and corners of the aquarium. After that wash it with clean water and wipe out.

Replacement Process   

Try to change 10% of water per week to maintain the quality but if you are busy with your schedule then try to replace about 25% of the water twice a month. This process is necessary to refine the contaminated water in the tank.

Rainbow Shark’s Appearance

This tiny territorial fish is infamous as an active swimmer, compared to other aquatic species. Also, you might have observed its slender and downward shape of the mouth because it’s a bottom-feeder and moreover, you will find its pair of glowing red or pink eyes on the small forehead and flattened curved spine. The females have red or orange tail-fin and the male have red or orange fins with black edges at the anal part.

The flat stomach of this tropical freshwater fish is pointed with a snout and upright dorsal fins which give it the appearance of a Shark. Usually, the female Rainbow Sharks are heavy-weighted compared to the male fish when they turn adult, and the male fish start growing their tail fin with small black lines when they are sexually matured.

However, as per veterinary medical practitioners, Rainbow Fish lose their colors when they are ill or stressed. So, feed your colorful friend properly to keep them strong and bright.

Dietary Plans of Rainbow Shark

If you are really interested to choose Rainbow Shark as a novel family member in your fish-jar then a proper nutritious diet is the necessary thing that would help you keep your swimmer friend healthy. Every fish has a separate diet, so you cannot maintain the same nourishment routine for all the aquatic breeds.

Rainbow Shark is an omnivore and scavenger fish that eats plants, meats, algae, decaying plants, insects, and larvae. Moreover, you will find these fish cleaning the fish tank by consuming the algae and waste products in the water. However, try to make a proper diet to keep your pet fish away from health issues. In a non-veg diet, feed them the following foods:

  • Wafers
  • Insect Larvae
  • Frozen Crustaceans
  • Zooplankton

While choosing a veg diet, add plenty of green vegetable crumbs and leaves such as:

  • Peas
  • Zucchini
  • Spinach
  • Lettuce

These diets will definitely help you keep the appetite and immune system of this breed strong so that infections cannot attack these species soon. Also, try to feed them frozen or live Bloodworms and Brine Shrimp to maintain their bright rainbow shades and blood level in their body.

You will also get dry and frozen fish food products with high nutrition values available in market like:

  • Tetra-Veggie Complete Diet for Algae Eaters
  • Fluval Bug Bites Bottom Feeder Formula
  • Hikari Tropical for Bottom Feeding Herbivorous Food

You should feed them 2-3 times in a day with five minutes gaps; remember over-feeding can be harmful to them as they have a very short life-span and their poor digestive system can be the reason of their short life, which is less than five years.

Rainbow Shark’s Behavior and Temperament

Along with its bright, swift and jolly nature, you may find aggression and dominating temperament in Rainbow Shark. Thus, make a hiding point in your aquarium, so that peaceful fish breeds can take rest or hide during or after a fight with this semi-aggressive terrestrial Shark.

Make sure the aquarium is large and they get enough place to swim. Usually, they fight with the bottom-dwelling fish, rather than higher water species because Rainbow Sharks live at the bottom of the water and seek plenty of space for themselves. Remember, their aggression may result in biting, head-tail butting and chasing other fish in the tank.

Try to choose accurate peaceful companions for them to make them social, but also restore calmness in the fish. Don’t forget to fix the lid of the aquarium properly because these sharks often jump higher than other fish. When they are small, they will spend their time hiding but once they turn adult, their active swimming and smart nature can be observed by the fish-keepers. However, their aquarium-cleaning behavior by eating the algae in the tank is often liked by the fish owners.

Suitable Tankmates of Rainbow Shark

If you are finding an active and bright fish then Rainbow Shark is definitely the perfect one, but if you are in the search of a calm-natured fish then it’s not the right breed for you. The semi-aggressive and wild nature makes these fish different from other tropical freshwater fish. So, carefully select new peaceful friends for your little flying-companion that are not aggressive but friendly in nature such as

  • Marled Hatchet Fish
  • Otocinclus Catfish
  • Barbs
  • Gourami
  • Danios
  • Rasboras
  • Plecostomus
  • Clown Loach

Try to avoid keeping bottom-dwelling and other aggressive fish to keep with Rainbow Shark because it can lead fight between them. These Rainbow Shark fish are envious of all the categories of sharks and other bottom-dwelling fish such as:

  • Bala Sharks
  • Royal Gramma
  • Red-Tailed Shark

Also, never keep two rainbow sharks that belong from the same family because this may start fighting to the death. So, avoid bloodshed of your little friends and choose compatible peaceful companions for your tiny aquatic partner.

Rainbow Shark’s Breeding

For taking proper care of your pet fish, you need to know the mating and reproduction functionalities of the species. The female Rainbow Sharks become much heavier than the male when they turn adult. When they are young, they are 4” (10 cm). Moreover, the male grows black anal fins in their adulthood and becomes sexually capable.

Usually, the abdomens of the female Rainbow Sharks become fat, rounded and greenish when they turn pregnant. The egg-embryos grow inside, and after they get mature, she lays eggs. After this, the male mates with the female fish thereby fertilizing the eggs with natural milt spray. Now, you need to keep the small fish in other well-aerated water-filled fish tank during its primary development which is one week after the fertilization of the eggs.

This is necessary because other fish can attack or eat the tiny new-born fish. Thus, let them learn to swim for a week then take them to that aquarium where their parents live. It is much preferred if you help the fish reproduce separately at the tank which is larger in size. However, if you have less idea about the breeding process, then you can also take extra ideas from aquarists or experienced fish-breeders.


Rainbow Sharks have sexual and reproduction functionality during winters from October to November. They choose the winter season as the best time of fertility because winter is the best time to hatch eggs, fertilize them and safeguard them naturally with the water temperature.

Diseases of Rainbow Shark with Prevention

Generally, the Rainbow Sharks are strong compared to other aquatic species but be careful of the diet, hygiene and breeding process of the particular fish breed because its immune system is usually affected adversely which is the prime source of different health issues such as Ich, Swim Bladder Disorder (SBD), Skin Flukes and Fungus. However, the major reasons for these diseases are poor water quality of the aquarium.

Always keep the water of your fish tank clean, so that your new aqua-loving friend does not consume the dirty water that is the source of various health infections. Remember, the water of the aquarium is the home of your tiny swimmer friends.

If you find any fish dying in the water of the fish tank then immediately remove it from the tank because the corpse can definitely be the reason causing infections like Ammonia Spikes and bacterial disease. If your pet fish consumes the infected water then it may get affected by life-threatening diseases related to appetite or digestion.

You can easily avoid illnesses of a Rainbow Shark by changing a portion of the water twice every week. Moreover, try to make a proper diet plan for them by feeding high-quality foodstuffs that are mentioned above but with a specific time gap. If you are not capable of maintaining prevention of your tiny buddy’s diseases then try intervention for the fish by consulting with expert aquarist or veterinary physician about its medicines and diets.

Types of Rainbow Shark Fish

You may also get variations in Rainbow Shark Fish and adopt some of them if you want. The bright colors and appealing looks of these cute fish are really adorable. Take a look at a few Rainbow Shark Fish that are natives of the same breed:

  1. Albino Rainbow Shark – Another name of Albino Rainbow Shark is Ruby Shark that is 15 cm long and belongs to the family of Shark. It is originated from the river basin of Indonesia. This fish has color variations, as some have a white body with red fins and tails, others have black or a gray body with red fins and tail. However, the rest of the features and care guide for Rainbow Shark Albino is the same as mentioned for Rainbow Shark in this article.
  2. Red-Tailed Black Shark – This shark belongs to the Rainbow Shark fish family with a black body and red or orange tail. This freshwater fish is also originated from Thailand, but compared to other Rainbow Sharks, this fish is less aggressive. So, you don’t need to worry much to choose its companions if you keep it in your fish-jar.

Difficulties in Keeping Rainbow Shark

If you have owned a new aquarium, and you are a beginner of fishkeeping then get expert suggestions to upkeep Rainbow Shark in your fish tank. By the above-mentioned discussion, hope you have a clear idea about the wild and aggressive nature of this breed.

The quarrelsome behavior and ragefull temperament of this aquatic creature make it one of the great intruders that fight with its aqua-mates until it dies. However, to avoid the activities like fighting, injury and bloodshed, try to choose calm-natured play-mates for Rainbow Shark that avoid enviousness. If you are ready to take the prevention then definitely you will overcome the challenges in giving a perfect homely environment to this terrestrial fish.

Care Guidance for Upkeeping Rainbow Shark

The comfortable amenities will delight your swimming-companion and will provide space with comfort for the breeds because providing a perfect living place to Rainbow Shark is the major thing it requires.

In the wild, the fish is found in running stream as mentioned above, so try to provide the same ambiance to your sweet pet fish by storing it in a huge-spaced aquarium with much clean and flowing water. For the high flow of water, you can keep air pumps and air stones. Always help them to get rid of stressful problems by feeding them properly.

Make your little buddy social by keeping it with good room-mates, and rejoice them by fixing standard lighting i.e. medium in the top-most part of the aquarium; always remember to off the lights at night. You can also try adding Rainbow-Lasts (colors) available in the market to reduce the wild nature of the Rainbow Sharks.

Try to include new members in the fish jar with the help of a floating bag and switch off the lights of the aquarium while doing that. After ten minutes, you can switch on the lights, this will lessen the spiteful nature of your colorful friend and help in settling its mood.

Don’t need to stress yourself much while breeding a terrestrial pet fish like Rainbow Fish, the aforesaid care guide will definitely help you bring the bright new member to your fish family. You just need to be cautious while following the care guide and necessities of the Rainbow Shark and its entire family while upkeeping them in your aquarium.

Interesting Facts about Rainbow Shark

  • Rainbow Sharks release their poisonous toxins to attack their enemies while required.
  • The mucus liquid in the body of the Rainbow Shark helps it in feeding the newborn babies.
  • The male rainbow Shark helps the female during the time of laying eggs.
  • These fish prefer living in cold and high-flow water body.

More Freshwater Aquarium Fish Aggressive Like Rainbow Shark

You can also collect new aquatic-companions that are similar to Rainbow Shark for your fish tank such as: