Iridescent Shark – The Complete Care Guide of This Shinning Pet Fish

Iridescent Shark on the substrate
By Garrison Hickles Updated

When we hear the name ‘Shark’, we are scared of its huge size, sharp teeth, and predator nature. However, many sharks are non-aggressive in nature and friendly in a community tank like Iridescent Shark. Its size is like Redtail Shark, but its temperament is not like that Shark.

Iridescent Shark is also known as Sutchi Catfish or Siamese Shark. If you are interested in keeping this fish in your aquarium, then you may get knowledge about its care guide for upbringing it.

Quick Details

As we have discussed above, Iridescent Shark is different than other fish breeds. It is a popular pet fish because of its peaceful nature. You can have a quick look at its details on this table.

Scientific Name Pangasianodon hypophthalmus
Origin Chao Phraya, Mekong (Asia)
Life-Span Up to 20 Years
Colors Silver with Dark Dorsal Fins
Temperament Peaceful
Size                48” (121.92 cm)
Diet Omnivore
Family Pangasiidae
Compatibility With Large Fish
Tank Size 300 Gallons
Care Level Moderate


Iridescent Shark belongs to the family of Mekong Giant Catfish, one of the largest tropical water fish in the world. If you want to keep this fish in your aquarium, then you need to arrange a large aquarium because at the juvenile stage it is small, but it can grow up to 4 feet or 48” (121.92 cm).

Fishkeepers admire this Shark because of its shinning and vibrant colors. Iridescent Shark is not a picky eater. It can eat anything you feed it. So, you have to be careful about its diet and nutrition. This fish is less affected by diseases because it is a hardy species of freshwater.


Some people eat Iridescent Sharks and others like petting them.

Origin of Iridescent Shark

Native to Southeast Asia, Iridescent Shark fish is found in the Chao Phraya River and Mekong River Basin. This fish is introduced to other rivers for aquaculture. Some of them are found in Magdalena River of Colombia and others are found in Kone Falls.

Appearance of Iridescent Shark

The name of this fish starts with the word ‘Iridescent’ which means shiny. The shimmering body of this fish brings electrical shine in the water of the fish tank. This Shark has two black stripes on the body, which is below the lateral line. This line is a vital part of its body because it is a sensory organ filled with nerve tissues. These tissues help the fish detect the changes in water.

The skeletons of this fish are made of cartilage, so people call them Cartilaginous fish. The black spots near the eyes, nose, and mouth of Sharks act as an electromagnetic receptor. Moreover, the skin of Iridescent Shark is like sandpaper.

When it becomes adult, its color turns uniformly gray from light gray or white. The females are plumper and larger than the males. This fish also has long whisker-like barbels which help in sense its environment.    

Diet Plan for Iridescent Shark

This fish is not a picky eater, so it can consume anything it finds. In the juvenile stage, this fish prefers eating live meaty foods. When it grows up, it starts eating vegetation alongside meat. This fish will eat anything you give it, so you have to maintain a balanced diet for this fish. If you have no idea about its nutrition and diet, take suggestions from an expert veterinary nutritionist about the diet schedule of the fish.

You can feed high nutritional live foods to this fish 2-3 times a day because live foods have protein which helps the Shark in growing strength and color. Do not overfeed the fish because it may pretend to be hungry all the time. Some favorite foods of Iridescent Shark are:

  • Crickets
  • Bloodworms
  • Brine Shrimps
  • Blackworms
  • Scallops

There are some readymade foods that you can feed your pet fish such as:

Tank Requirements for Iridescent Shark

This fish prefers living in deep rivers near Thailand, especially in the Mekong River. This migratory fish swims upstream to spawn. It prefers living in the middle part of the aquarium. Take a look at more information for the tank setting of Iridescent Shark:

Tank Size

The tank size of this Shark should be 3000 gallons because this fish prefers living in a spacious aquarium. If you want to keep this fish in your aquarium, then buy a 1000-gallon tank for one Shark and purchase a 3000-gallon tank for 3-4 Iridescent Sharks.


Iridescent Shark is different than other fish breeds. It does not need many plants or rocks in its aquarium. Keep some fast-growing plants like Anacharis and Hornwort in the tank. Also, keep a sandy substrate at the bottom of its tank. Rocks and pebbles are not needed for its aquarium.  


This shark is a nocturnal species, meaning it is active at night, so you need to mount a moderate light on the topmost part of the aquarium of this fish because it does not like harsh light.


You should keep a powerful filter in the aquarium of Shark because this fish is a messy breed, which leaves uneaten foods in the tank. Moreover, the poops of the fish contaminate the water of the aquarium, which can be refined by a good filter.

Water Type for Iridescent Shark

Iridescent Shark prefers living in warm water, so arrange a heater for its tank. Moreover, maintain the parameter of the water of this fish by checking the temperature, hardness and pH level.


The temperature of the water in the tank of Iridescent Shark should be 72-79 °F (22.22-26.11°C). This fish can’t live in cold water, so it is necessary to keep a heater in its tank.  

pH Level

The pH level of the water of the tank of Iridescent Shark must be 6.5-7.5.


The hardness of the water in the tank of this fish should be 2-20 dGH, and the water movement should be moderate.

Cleaning Method

You should clean the tank of this fish twice in a month because Shark is a messy fish. If its home is not clean, then it may get affected by various diseases. So, collect a brush, liquid soap, and cotton cloth to clean the tank. After brushing and washing out the dirt, wipe out the walls and decorations of the tank with a clean cotton cloth.

Replacement Process

Change 20% the tank water of this fish every week to maintain the quality of the water, as we have discussed that this fish is messy in nature and pollute the water with uneaten food and its poops.

Temperament of Iridescent Shark

Although it is a peaceful fish, its large size is scary. It does not like loud noise and prefers living in a silent place. If its tank is overcrowded and loud noise passes around its tank, it becomes aggressive and starts hitting its head on the glass or decorations of the aquarium.

When these fish are at a juvenile stage, they school together, but when they become adults, they live separately.  

Suitable Tankmates for Iridescent Shark

You can keep Iridescent Shark with large peaceful fish but avoid keeping them with aggressive and small fish. Aggressive fish can fight with them and small fish should be avoided in a Shark’s tank because they may eat up the small fish. It will be better if you keep the same sized fish breeds in the tank of Shark. The best companions of Iridescent Shark are:

  • Pearsei
  • Plecostomus
  • Synodontis Catfish
  • Silver Dollars
  • Leptobotia Elongata Loach
  • Kissing Gourami
  • Fire Eel
  • Texas Cichlid
  • Salvin’s Cichlid
  • Oscar

Unsuitable Tankmates

Don’t keep small fish and crustaceans in the tank of Iridescent Shark because it can eat up the small species. Also, keep this fish away from rageful and large fish breeds that can attack or fight with this fish. Have a look at a few unsuitable tankmates of this fish:

  • Danio
  • Barb
  • Tetra
  • Molly Fish
  • Piranha
  • Redtail Shark
  • Silver Arowana
  • Crustaceans or Invertebrates


You can keep a maximum of four Iridescent Sharks in a 3000-gallon fish tank so that they can dwell peacefully. Iridescent Shark does not prefer an overcrowded tank.

Breeding of Iridescent Shark

It is hard for this fish to lay eggs in captivity. The mating and breeding season of Shark is late spring or early summer when the water level rises upward. Most of the Sharks are comfortable in laying eggs in the middle level of the ponds and streams.

You need to provide a separate large tank for the breeding process of Iridescent Shark because it feels challenging to spawn and breed in captivity. After breeding, separate the eggs from their parents. Keep the parents in the existing tank and let the eggs fertilize and grow themselves Feed small Brine Shrimps and newborn Bloodworms to the baby fries and keep floating plants in its tank, so that it feels comfortable.   

Diseases of Iridescent Shark with Intervention

Iridescent Shark is a nervous fish that gets scared easily by hearing any noise. So, don’t stress them or disturb them by knocking the glass of the fish tank, which may lead to the panic attack of the fish.

Usually Sharks have good eyesight, but this fish has poor eyesight, so try to give high protein meaty foods like Brine Shrimp, Bloodworms and other crustaceans to this fish from an early age. If the water of the tank of this fish is not clean, and the parameter is not maintained, then it may get affected with various diseases such as:

Try to know the root of the infections and get suggestions from a veterinary doctor. Without a valid prescription from a doctor, don’t give any medicine to your pet fish because many medicines have side effects that may harm the fish.

Difficulties in Keeping Iridescent Shark

Although Iridescent Shark is a hardy and peaceful fish, the breeding process of this fish is tough for beginners. This fish feels uncomfortable to reproduce in captivity. So, an expert aquarist can help you know its exact breeding process in an aquarium. Therefore, beginners are suggested not to encourage the breeding process of this Shark.

Neither it is too tough, nor is it too easy to keep this fish in your aquarium. Follow our complete care guide to keep this pet fish comfortably in your tank.

Interesting Facts

  • Iridescent Shark does not have bony plates over its body, so it is known as ‘Naked Catfish’.
  • Most of the Sharks, including Iridescent Shark, has cold blood in their bodies.
  • The embryos of some Sharks attack each other.
  • Shark’s bite is poisonous like a jungle cat.
  • Multiple male partners can impregnate a female Shark.
  • Shark never sleeps.

More Information about Other Sharks of your Aquarium

Not only Iridescent Shark, but there are also many other Sharks that you can keep in your aquarium. Just take a look at its complete care guide if you are planning to add these fish in your aquatic home.