June 28

Sarah Robertson

Do You Have What It Takes to Care for an Iridescent Shark?

Catfish comes in a variety of colors, but one of the most beautiful – and popular – is the iridescent shark. Even though it's called a shark, it is actually a member of the catfish family. It is also known as the siamese shark or Sutchi Catfish.

The iridescent shark aka iridescent catfish is a very large freshwater fish that only the most prepared aquarists should keep. They are easily distinguished by their large size and coloration. If you want to keep one of these beauties in your aquarium, make sure you know what you're getting into. This guide will teach you everything you need to know about iridescent sharks, from their care and diet to their behavior and tank mates.

Iridescent Shark Origin

Iridescent sharks can be found in various areas of Southeast Asia. They're tropical freshwater fish that prefer deep and broad rivers with plenty of space to swim about.

They are stored in two of Southeast Asia's biggest rivers, the Mekong and the Chao Phraya. These big rivers are ideal since they allow them to cover a large area when they flow at various times throughout the year.

In certain locations, iridescent sharks are harvested and raised for food because of their size and price. The swai food market name is applied to these fish.

Iridescent Shark Appearance 

Iridescent catfish are fascinating creatures. While some people consider many catfish to be a little dull in terms of aesthetics, it's difficult to deny the wonderful appearance of these fish.

Their unusual dorsal fin is one of the first things that catches your eye. It resembles a sail and will fan out or tuck back depending on how the fish swims.

When they're first born, iridescent sharks have very dark, glossy skin. Their skin becomes duller and darker as they get older, turning into a dark, solid grey. This may cause people to mistake them as adults because their skin becomes less glossy and more opaque with time.

The long whiskers on catfish make them appear to have classic "catfish" features. These are used by them when they're navigating in areas with limited visibility. One thing you'll notice is that these fish have enormous eyes! This is particularly apparent when they're younger (when they gradually become bigger).

The caudal fin of the iridescent shark (which is also known as a rainbow shark) has identical sail-like tissue to its dorsal fin. Their anal fins stretch from the flat part of their belly to the base of their tail. The size of an iridescent shark is one of the most important factors in determining whether it's appropriate for your aquarium.

Behavior & Temperament 

These are schooling fish that do better in groups. When alone, they're far more likely to be stressed and worried, but in a group, they're much calmer. If you only have one fish, you'll notice a lot more retiring and nervous behavior.

These fish have a calm disposition and don't cause any problems for other fish. They don't usually display signs of aggression and are rather docile.

Sometimes when an iridescent shark gets scared it might dart or splash around a bit. This can be mistaken as a sign of aggression by new owners, but that’s rarely the case.

In general, these fish are quite docile and get along with almost any other freshwater species. The only time you should be concerned about aggression is if you're keeping them with rainbow sharks or red-tailed sharks.

Iridescent Shark Size 

When fully grown, the average iridescent shark length is 3-4 feet. Their size is one of the most challenging aspects for owners to deal with. People who do not realize their maximum size or growth rate frequently buy these fish. This causes the health of the fish to suffer because the tank is not large enough to accommodate them.

Before you buy a huge fish, make sure you're ready to care for it. While iridescent sharks are interesting pets, they aren't for everyone.

Iridescent Shark Lifespan

Iridescent Shark Lifespan 

An iridescent shark's lifetime is typically 20 years long. This can differ based on the quality of care they're given. If they're raised in poor conditions, their lifespan will be shorter.

Iridescent Shark Tank Setup 

Even though these fish are comparatively easy to care for, there are many things you should take into account when setting up their tank. The following list includes some of the most important:

Tank Size

A 300-gallon tank is suggested for an iridescent shark when it is fully grown. They'll need enough space to swim freely and be comfortable in this size tank.

In most cases, these fish are kept in much smaller aquariums at first and gradually transferred to larger and more magnificent facilities as they mature. While this is a successful approach, it's vital to make the change before they're ready rather than after.


A filter is an essential piece of equipment for any aquarium. It helps keep the water clean and removes toxins and other harmful chemicals.

There are many different types of filters available on the market. While canister filters are a good option, hang-on-back (HOB) filters are also popular for this fish species.

It's recommended that you choose a filter with a flow rate of at least 6 times the volume of your tank. So, for a 300-gallon tank, you should get a filter with a flow rate of 1800 gallons per hour (GPH).

Water parameters 

Iridescent catfish are tough, which allows you some wriggle room when it comes to water conditions. It should not be difficult to maintain the ranges indicated below.

pH level:


Water hardness:



72-80°F (24-27°C)

Despite the fact that these are hardy fish, you should check the water conditions on a regular basis. It may take longer to reverse these levels in larger tanks. This is especially true if you have no prior experience with big tanks.

It's always simpler to detect issues before they become an issue than trying to repair things after everything has gone horribly wrong.

Tank Decor 

Your iridescent shark will appreciate some hiding places in its tank. They're naturally shy fish, so they'll feel more comfortable if they have somewhere to hide.

Caves, rocks, and driftwood are all good options. Just make sure that whatever you use is safe for your fish and won't release any toxins into the water.

You can also add live plants to your tank. This is not only aesthetically pleasing, but it will also help keep the water quality high. Some of the best plants for freshwater aquariums include java fern, Anubias, and water sprite.


The substrate is the material at the bottom of the tank that your fish will be swimming over. It's important to choose something that won't harm their fins or get caught in their gills.

One option is to use small, rounded gravel. This is a good choice because it won't hurt their fins and they can't ingest it by accident.

Another option is to use sand. Sand is becoming increasingly popular as an aquarium substrate because it has a natural look. It's also easy to clean and maintain.

If you choose to use sand, make sure you get one that is labeled as aquarium-safe. Some types of sand can release harmful toxins into the water.

Tank mates 

The finest iridescent shark tank companions are peaceful fish of comparable size. Anything much smaller may be mistaken for a snack (which you don't want). So they must be kept with similar or larger fish.

Suitable tank mates for an iridescent shark include:

  • Bichir
  • Oscar fish
  • Silver dollar fish
  • Large plecos
  • Black shark
  • Tinfoil barbs

Always do your research before adding any fish to your tank. You need to make sure they will be compatible with your other fish and that they have similar care requirements.

Iridescent Shark Food

Iridescent Shark Food

In the wild, these fish are opportunistic feeders. This means they'll eat whatever they can find. Their diet typically consists of small fish, crustaceans, worms, and insects.

In captivity, they're not picky eaters either. They'll accept most types of food, including

  • Pellets: These are a good option because they contain all the nutrients your fish needs.
  • Flakes: Flakes are also a good option, but make sure you get high-quality flakes that are designed for large fish.
  • Frozen/live food: Frozen or live food is a great way to add some variety to your fish's diet. It's also a good way to get them to exercise. Some good options include brine shrimp, bloodworms, and daphnia.
  • Live foods: Live foods are the best option, but they can be expensive. If you can't afford to feed your fish live food all the time, frozen is the next best thing.

It's a good idea to feed them a varied diet or balanced diet to ensure they're getting all the nutrients they need. This is especially important if you're only feeding them pellets or flakes.

How Much and How Often?

As a general rule of thumb, you should feed your fish 2-3 times per day. Each feeding should be small enough that they can eat it all in a few minutes.

If you're not sure how much to feed them, start with a small amount and increase it as needed. It's better to underfeed them than overfeed them.

Overfeeding is one of the most common mistakes new aquarium owners make. Not only does it lead to water pollution, but it can also be harmful to your fish.

Signs of Overfeeding 

One of the easiest ways to tell if you're overfeeding your fish is to look at the tank water. If it's cloudy or has a strange odor, it's a sign that there's too much waste in the water.

Another sign of overfeeding is if you see uneaten food sinking to the bottom of the tank. This means your fish are eating more than they need and the excess is going to waste.

If you see either of these signs, reduce the amount of food you're giving them.

Iridescent Shark Diseases

Like all fish, iridescent sharks are susceptible to a variety of diseases. The most common ones include:

Ich: Ich is a parasitic infection that causes white spots to form on the fish's body. It's often fatal if left untreated.

Fin rot: Fin rot is an infection that causes the fins to become discolored and eventually fall off. It's often fatal if left untreated.

Dropsy: Dropsy is a condition that causes the fish's body to swell up with fluid. It's often fatal if left untreated.

Skin Fungus: Skin fungus is a fungal infection that causes the skin to become discolored and covered in white patches. It's often fatal if left untreated.

These are only a few of the diseases that can affect iridescent sharks. If you think your fish is sick, it's important to take them to a vet as soon as possible.

Symptoms of Disease 

The following are some symptoms that may indicate that your fish is sick:

  • Loss of appetite
  • Lethargy
  • Gasping for air
  • Clamped fins
  • White spots on the body
  • Ulcers on the body
  • Swelling of the body

If you notice any of these symptoms, you should take proper action right away. The sooner you treat the disease, the better the chances are that your fish will recover. You need to quarantine the fish in a separate tank and treat them with a commercially-available treatment.

Preventing Disease 

The best way to prevent disease is to maintain a clean and healthy environment for your fish. You should do the following:

  • Change the water regularly
  • Clean the filter regularly
  • Remove any uneaten food from the tank
  • Don't overfeed your fish
  • Quarantine new fish before adding them to the tank
  • Checking the water parameters regularly

If you do all of these things, you will create a healthy environment for your fish and reduce the chances of them getting sick.

Iridescent Shark Breeding

The Iridescent Shark is a species of freshwater shark catfish, not a shark. They are migratory fish and cannot be maintained in aquariums due to their enormous size when full-grown. Young iridescent sharks come from Thailand's rivers and prefer to travel in schools, but as they get older, they become more solitary.

They are beautiful, colorful fish that make excellent house pets. Unlike other catfish, they do not cling to the bottom of a tank. They will congregate in the center and have been known to venture above the water to be stroked. It's notoriously difficult to breed Iridescent sharks in captivity, but there are things you can do to increase your chances of success.

Buy a school of iridescent sharks, both male and female. Set them in a huge pond (in the tens of thousands of gallons or more). Because their complete adult size can be 3 feet or longer, this big swimming space will be critical for mating.

Create a pond with moving water to replicate the natural environment for iridescent shark species. This is similar to the rivers that are their natural spawning habitat. If you want to mimic a river, consider having two ponds with water flowing between an inlet and an outlet for each. The current should be strong enough to keep the sharks from being able to rest, but not so strong that it washes them away.

Keep the pond's water temperature at least 70 to 75 degrees Fahrenheit. Keep a pH of 6.5 to 7.5 as well. Every day, offer your shark catfish fish pellets, brine shrimp, and other plants with a diet of both dead and live foods. They are omnivores that aren't picky eaters, so a variety of foods will help ensure they're getting the nutrients they need.

Look for females that are carrying eggs in the spring or summer if they are fully grown. The males will fertilize the eggs that the females deposit.

Remove the parents from the breeding pond after they have spawned. The fry will develop over a period of two to three weeks. They can be moved to a separate tank when they are free-swimming and big enough to eat on their own.

Note: It will be difficult or nearly impossible to breed iridescent sharks in captivity. They need specific circumstances, and they must have a lot of space and enough water depth to swim about in order to simulate their natural habitat. You may attempt for many months and fail before you are able to produce iridescent sharks.

Iridescent Shark Breeding


How do you take care of an iridescent shark?

The best way to take care of an iridescent shark is to maintain a clean and healthy environment for your fish. You should do the following:

  • Change the water regularly
  • Clean the filter regularly
  • Remove any uneaten food from the tank
  • Don't overfeed your fish
  • Quarantine new fish before adding them to the tank
  • Checking the water parameters regularly

If you do all of these things, you will create a healthy environment for your fish and reduce the chances of them getting sick.

What temperature should water be at for an iridescent shark? 

The preferred water temperature for an iridescent shark is 72 to 80 degrees Fahrenheit.

What do iridescent sharks eat?

Iridescent sharks are omnivores, which means they will eat both dead and live food. Some of the food they like to eat includes fish pellets, brine shrimp, and other plants.

Can iridescent sharks live alone? 

No, iridescent sharks are social creatures and need to be in a school in order to thrive.

Do iridescent sharks grow to be big?

Yes, iridescent sharks can grow to be 3 feet long.

How difficult is it to breed iridescent sharks?

It is notoriously difficult to breed iridescent sharks in captivity. This is because they need specific conditions in order to spawn, and their fry needs a lot of space to swim about. You may attempt to breed them for many months and not be successful.

Do iridescent sharks lay eggs? 

Yes, female iridescent sharks lay eggs which are then fertilized by the males. The eggs hatch and the fry develop over a period of two to three weeks.

Do iridescent sharks play dead?

No, iridescent sharks do not play dead. This is a myth that has been perpetuated by the movie Sharknado.

What should I feed my iridescent shark?

Iridescent sharks are not picky eaters and will eat a variety of food. It is important to feed them a diet that is both nutritious and varied. Some of the food they like to eat includes fish pellets, brine shrimp, and other plants.

Do iridescent sharks have teeth?

Yes, iridescent sharks have teeth. However, they are not as sharp as the teeth of other shark species.

Do iridescent sharks need a lot of space? 

Yes, iridescent sharks need a lot of space to swim about. They should be in an aquarium that is at least 50 gallons.

Do iridescent sharks make good pets?

Yes, iridescent sharks can make good pets. They are relatively easy to care for and are interesting fish to watch. However, they do need a lot of space, so you need to be sure you have an appropriately sized aquarium before you get one.


Iridescent sharks are interesting and unique fish that can be kept in any aquarium. They are not aggressive fish and can make good pets. Iridescent shark care is relatively easy, however, you must be well prepared before you get one.

They need a lot of space to swim about, and you need to have a larger tank or appropriately sized aquarium. Maintaining a clean and healthy environment is also essential to keeping your fish happy and healthy. You should also be aware that it is notoriously difficult to breed them in captivity. But if you are up for the challenge, then iridescent sharks can be a fun and rewarding addition to your home.

Sarah Robertson

I am a passionate blogger who also happens to be a fish keeping enthusiast. Writing about my hobby is something that I absolutely love to do, and it's no secret that my chosen topic is always centered around fish keeping.

Sarah Robertson

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