Iridescent Shark: Size, Food, Tank Mates, Care…

The Iridescent Shark is not really a shark at all.

This gigantic fish is actually a type of river Catfish!

Despite their size this is a peaceful and docile fish. However, they must be taken seriously. They should only be kept by experienced fish keepers who have the time, money, and space to maintain such a large habitat.

Are you ready to take on an Iridescent Shark?

Keep reading to learn everything you need to know to house and care for this massive fish…

Related: Top 15+ Freshwater Aquarium Sharks For All Tanks

Iridescent Shark

Iridescent Shark Overview

The Iridescent Shark (Pangasianodon hypophthalmus) is a giant Shark Catfish native to Southeast Asia.

This Giant Catfish can grow up to 4 feet long (48 inches) and is related to some of the largest Catfish in the world, including the Mekong Giant Catfish and Paroon Shark.

They belong to the Pangasiidae family and can be found in the Mekong and Chao Phraya Rivers, as well as other rivers in Thailand, Vietnam, Cambodia, and Laos.

Just like the Red Tail Shark, Iridescent Sharks are loved because of their size.

They are most commonly kept by people looking to create an authentic river biotope. Although they can be kept in indoor tanks, they are much better suited for outdoor ponds. You will need at least a 300 gallon tank if you want to keep one indoors.

You will not find this fish at a pet store. A reputable tropical fish breeder or a specialty monster breeder is your best option.

The $25 to $50 price tag for this fish does not include the price of their enclosure and equipment, which can run all the way up to $1200.

Key Facts:

  • Experience Required: Intermediate.
  • Nicknames: Sutchi Catfish, Tra Catfish, Siamese Shark Catfish.
  • Color Forms: Silver.
  • Size: 48 inches.
  • Tank Size: Minimum 300+ gallon.
  • Tank Temperature: 72°F-80°F.

Iridescent Shark Full Grown


  • Graceful and beautiful
  • Can be kept with other large fish
  • Fantastic for a natural biotope
  • Good for pond pest control

  • Very expensive care and maintenance
  • Difficult to keep indoors
  • Easily stressed or scared

Appearance and Size

Iridescent Shark Juvenile Size
Juvenile Iridescent Shark

This fish’s most notable feature is their incredible size!

Juveniles are typically sold between 3 to 5 inches long but fully grown adult Iridescent Sharks can grow all the way up to 48 inches long.

They will initially be bright white or silver with iridescent scales, but as they mature their color darkens to silver and finally gray. The iridescence remains until the fish reaches their senior years. Younger fish sparkle in all of the colors of the rainbow when the light hits them, while older fish have a silver shine.

Their body shape is similar to a marine shark. All of their bulk is contained in the center of their body, and their head is a wide and triangular shape.

Similar to most other Catfish they have two long barbels on the side of their face. These barbels are used for detecting movement, vibration, and even chemical changes in the water column.

Iridescent Sharks do not have the same thick, plated scales that other Catfish have. Instead, they have tiny, thin scales that fit together like a chain.

There are also two alternative varieties for this fish:

  • Albino: An albino shark is stark white, with pale pink spots across their body. Their fins can be yellow, red, or orange.
  • Short-body: This morph was bred with smaller tanks in mind. They have a round, compressed body with visible balloon bellies, and only reach around 20 inches.

Habitat and Tank Conditions

In the wild you can find Iridescent Sharks in the deepest areas of rivers and ponds.

They group together in wide, open waters with muddy riverbeds.

Water temperatures usually reach between 75-77°F and the salinity is highly variable, from pure freshwater to brackish. These fish prefer the areas of the river with the fastest flow.

While there may be underwater plants around, they do not use them as shelter, but as food.

Ideal Tank Set Up

When setting up their habitat, size and depth are the most important things to consider.

An indoor tank must be at least 300 gallons, with a depth of 24-30 inches. Outdoor ponds should be about 9 feet long, 9 feet wide, and 3 feet deep.

Tank Parameter Requirement
Minimum Tank Size 300 Gallons
Tank Type Freshwater
Temperature 72-80°F
pH 6.5-7.5
Hardness 10 dGH
Flow Medium to Heavy
Substrate Mud

You will need to emulate the fast flow of an open water channel. You can do this by using a canister filter with adjustable flow, or by adding a pump. In an indoor tank the light should be about 4 to 5 watts per gallon for 10 to 12 hours a day. In a pond you can rely on natural sun exposure.

Sometimes Iridescent Sharks will try to eat the equipment so you should place everything out of reach. If possible, use external filters and heaters rather than anything that is placed directly into the tank.

Decorations can also be munched on or knocked over, so you will need to make sure that they are safe. You should not include any sharp decorations that may injure their skin or their barbels. The safest way to decorate your shark’s enclosure is to only use what they would find in their natural habitat, such as large boulders and logs.

You do not want to bother aquascaping this habitat, as this fish will eat most plants. You can include a few floating plants such as Hornwort and Cabomba if you want to.

What Size Aquarium Do They Need?

You will need a 300 gallon tank to keep just one Iridescent Shark.

Add 150 gallons for each additional specimen.

Group of Iridescent Sharks

Iridescent Shark Tank Mates

Despite their intimidating size this fish is surprisingly community friendly.

The secret is to pair them with other large fish that will not harass or bully them.

Iridescent Sharks are timid and will not pick fights with other fish. They also will not defend themself if another fish picks a fight with them.

If you have the right size pond then you can create a community of other magnificent monster fish.

Other large Catfish, such as the Synodontis, Raphael Catfish, and Giant Pleco, all make good tank mates.

Cichlids such as the Oscar or the Rio Grande will not pose any threat to this catfish either. You can also include a Bala Shark or a Black Sharkminnow. The Tinfoil Barb is another good choice, as is the Silver Dollar fish.

You can keep some truly unusual creatures in this community, including the Fire Eel and the Bichir.

Although this is a peaceful fish they will eat anything they can fit into their mouth. This means that invertebrates like shrimp and snails are not safe.

Aggressive or predatory large fish should also be avoided.

This means that species like the Arowana, Pacu, or Clown Knifefish should be kept away.

Keeping Iridescent Sharks Together

In the wild these fish will naturally school in groups of 5 or 6.

A school of fish will engage in communal feeding and travel in the same direction. They will direct one another to good feeding spots and safe areas of the tank or pond.

However, to do this in your home aquarium or pond, you will need a huge enclosure.

Each shark must have 150 gallons of water, in addition to the 300 gallons needed for your first shark. It is not recommended to keep a school of these fish in an indoor enclosure.

Care Guide

Pangasianodon hypophthalmus

This species is only suitable for experienced keepers.

Their massive habitat requires daily, weekly, and monthly maintenance.

Water changes can be very time consuming with a tank of this size. When performing a water change you should only replace up to 30% of the water in the tank. In an outdoor pond you will also need to perform seasonal maintenance, such as winter preparation and summer weeding and insect control.

If their water conditions are poor then they will let you know by banging their head against the sides of their enclosure.

Make sure that there is enough open water to stop this from happening.

Because Iridescent Sharks have very thin scales, fungal infections are very common.

A fish with a fungal infection will have a rash, lesion, or some other form of skin discoloration.

The fish may rub itself against any available surface to relieve the itching, including the walls of the tank or pond. Most fungal infections can be treated with medication. You can also kill off the fungus by adjusting the water temperature, salinity, and pH.


So, what do Iridescent Sharks eat?

This fish will eat anything that it can fit in its massive mouth.

Freshwater shrimp, snails, worms, frogs, and zooplankton are all on the menu. The fish will also eat plants and algae.

A fish this size needs a lot of protein in their diet.

You can purchase protein flakes made especially for large Catfish. These flakes can be supplemented with live prey, including: bloodworms, earthworms, brine shrimp, grass shrimp, crickets, flies, snails, or feeder fish.

Pond dwelling fish will munch on the weeds and algae that grow in the pond. They may even munch on pesky insects and worms.

There is quite a lot that this big fish can eat:

  • Flakes
  • Brine shrimp
  • Earthworms
  • Bloodworms
  • Grass shrimp
  • Feeder fish
  • Snails
  • Crickets
  • Flies
  • Insect larvae
  • Plant material
  • Algae

These will need to eat a lot over the course of the day. You should give them up to 3 meals every day.

They will get bored if you give them the same foods at the same times each day. You should give them something different every day, such as Catfish flakes one day and feeder fish the next.


You may be surprised by how timid this fish can be.

They will avoid the other fish in the tank and only socialize with their own kind.

Iridescent Sharks will swim in the middle of the tank and the open water area of the pond. They travel in schools when they are young and will continue to school as an adult if their habitat is large enough.

A unique behavior to watch out for is head banging.

When they are distressed they will bang their head against the sides of the tank. This can happen when they are scared, their environment is too small, or they are being harassed by a boisterous tank mate. In addition to being scared by tank mates, this fish can be disturbed by noisy filters or pumps. They can also be startled if you make a loud noise or a sudden movement.

Breeding Iridescent Sharks

Unfortunately you cannot breed Iridescent Sharks in a home aquarium or pond.

In the wild they travel upstream to the lower salinity areas to spawn in ponds and lakes. Their breeding season runs from March to August. It is impossible to simulate this migration in captivity.

Professional breeders encourage them to breed by raising their water temperature to about 82°F. With no ability to migrate, these fish must be bred through artificial means, such as hormone injections, and artificial fertilization by harvesting the eggs and sperm.

These fish can lay over 100,000 eggs at a time. How quickly the eggs hatch depends on the water temperature. In a temperature over 80°F, they hatch in about 2 days.

After they hatch the larvae will live off of their yolk sacs for an extra 2 days. Once they lose the yolk sacs they are fed with larval brine shrimp.

Juvenile sharks are ready to be shipped out once they reach about 3 inches long. It takes about 2 to 3 years for them to reach maturity.

Breeding these fish can only be done in a professional setting and should not be attempted in a home aquarium or pond.

History and First Sighting

The Iridescent Shark was first discovered by Henri Sauvage in 1878.

It was found in the Mekong River and at the time of their discovery, no one was thinking about keeping this fish as a pet, but as food! It was caught, harvested, and raised for food in Vietnam and Thailand.

During the 1960s shark meat was exported outside of Vietnam to the rest of Southeast Asia. The meaty fish became a delicacy, and the fish helped develop a booming aquaculture industry.

In 1996 they gained popularity in India and were soon introduced to Europe. It was in Europe that they were introduced to the pet trade.

Because this fish was already heavily farmed, the methods and materials needed to breed this fish were already known. This led to its success as an aquarium and pond pet.

Although today they are not the most popular fish in the tank, they do hold a loyal following among monster fish enthusiasts.

Species Summary Table

Iridescent Shark
Other Common Names: Sutchi Catfish, Iridescent Shark Catfish, Siamese Shark Catfish, Tra Catfish
Scientific Name: Pangasianodon hypophthalmus
Family Name: Pangasiidae
Distribution: Southeast Asia
Size: 48 inches
Color: Silver
Care Level: Intermediate
Temperament: Peaceful
Lifespan: 20 years
Minimum Tank Size: 300 gallons
Tank Mate Compatibility: Other large and peaceful fish

Should You Keep The Iridescent Shark? (Summary)

This giant Catfish is only suitable for experienced keepers.

Although they are small as a juvenile, by the time they are 5 years old, they will be 4 feet long!

You will need at least a 300 gallon tank and all of the equipment that is necessary to keep it running. The price tag can reach over $1000.

Iridescent Sharks thrive when kept in a pond.

Once you get everything set up, an Iridescent Shark is a 20 year commitment. But if you are willing to put forth the time and effort to care for one, it will be a truly rewarding experience!

How big has your Iridescent Shark grown?

Let us know in the comments section below…