Iridescent Shark 101: Size, Lifespan, Growth, Care & More!

What if you could have your very own shark at home? Interested? Then the Iridescent Shark might just  be for you. While technically a catfish, this freshwater fish has all the appearance of a beautifully intimidating shark, with the temperament of a little Guppy. Now if that isn’t the perfect combination, I don’t know what is.                                

The table below gives a quick overview of the Iridescent Shark profile:

Profile AttributeValue
Care DifficultyModerate-Advanced (space requirements)
Lifespan15-20 years
Color(s)Iridescent blue-green (juvenile)/ uniform dark gray (adult)
Maximum SizeUp to 4 ft. long
Minimum Tank Size300 gallons
Tank SetupFreshwater
CompatibilitySchooling fish

Below is our Iridescent Shark care guide, Continue reading to find out more about its Lifespan, Tank Mates, Diet and More.

Iridescent Shark Overview

The Iridescent Shark (Pangasianodon hypophthalmus) goes by many names. Some of these include Iridescent catfish, Sutchi catfish, Striped catfish, Hammerhead, and Siamese shark. Technically a species of shark catfish, this migratory freshwater fish is native to large rivers in Southeast Asia. 

In many parts of the world, the Iridescent shark is popular both as an aquarium pet, and a scrumptious delicacy in culinary circles. In the tank, they can be shy and reserved, and even have a propensity of being stressed by chaotic environments. This species of catfish has an elegant type of beauty, dark-colored and capable of growing up to a monstrous 4 ft long. They prefer belonging in groups and having generous swimming space as well. Naturally, because of these requirements, they are probably not the easiest fish to keep. But for those that can spare a lot of tank space, getting an Iridescent shark is a no-brainer. 


As previously mentioned, the Iridescent Shark is no real shark. The adults are dark-colored as well. So what’s up with the name? The answer is mainly because of how their juveniles look. Juvenile or young Iridescent Sharks typically have a shiny, multi-colored appearance. Couple that with their ‘shark-like’ dorsal, anal, caudal fins and ta-da! But unlike real sharks, these ‘sharks’ have two pairs of long maxillary barbels around their mouths; so they are actually more like sharks with mustaches.

As juveniles, you can hardly set male and female genders apart. All young Sutchi catfish have the same physical appearance. They have huge eyes, dark stripes along their lateral line, the middle of their anal fin, and on their caudal lobes. Their main body color is shiny and iridescent-looking, with a blue-green tint depending on the light. 

Upon reaching adulthood, these colors change and become a matte, velvety dark gray. This matte appearance is due to them being scaleless. The stripes become faint or nonexistent as they grow into adults as well. Soon, you can also start differentiating the guys from the gals. Obvious changes begin to occur once your catfishes reach around 12-15 inches. The females become larger and plumper than the males, with lighter stripes.

Tip: While their common color is a dark, velvety gray, there is an Albino variation of the Iridescent shark. Albino Iridescent sharks are  a stunning pale white, with red eyes. They’re beautiful and rare, so if you want to get one, it’s gonna cost you.

Average Size

These are monstrous-sized fishes. Juvenile Iridescent sharks are typically only around 2.5-4 inches in length. That sounds very manageable, but with proper care these little guys can grow to a foot in a single year! 

The truth is, Iridescent sharks or Striped catfishes can grow up to sizes of around 4.3 ft or 130 cm! Adult Iridescent Sharks can not only grow beastly in length either, but in weight as well. Capable of weighing up to around 97 lbs, many owners who buy them as juveniles are often shocked and ill-prepared once these fishes grow to adulthood. 

Of course, these sizes are heavily influenced by both the care shown to them, and the sizes of their tanks in captivity. Most of the time, Iridescent Sharks’ growth is stunted by the confines of their glass home.


In the wild, Iridescent sharks are known to live exceptionally long lives of up to 20 years. That’s about a fourth of an average human life! Their average lifespan is estimated at 15-20 years, however in captivity, this lifespan is often slashed. This is caused by many factors such as wrong tank mates, poor water conditions and diet. Most of all, many times the aquarium is too small for the Iridescent shark, resulting in premature deaths. 

Iridescent Shark Care 

If you want to know how best to not only extend your Iridescent Sharks’ lifespan, but also give it the best possible care, read on. We’ll tell you everything you need to know about your catfishes-i mean, sharks.

Tank Size

Iridescent sharks are large, schooling, and active swimmers. Mix those three factors and you’ve got yourself a need for a huge tank. Remember that in nature, Iridescent sharks live in large rivers and are migratory fish. They live to swim in open waters and be with other Iridescent sharks. 

For some owners, a 50 gallon tank is good enough for one juvenile Striped catfish, while a 300 gallon tank is suitable for an adult one. You can follow the rule to add around 150 gallons to this for every additional shark you have. Few fish enthusiasts ever have this much space in their homes however. You absolutely cannot sacrifice tank size for this fish species; it is their main requirement. Because of this, most aquarists agree that a heated pond is the best place to keep Iridescents and their friends.

Water Parameters

Striped catfishes or Iridescent sharks are native to the large rivers of Southeast Asia. Once your tank is readied, it’s time to know the optimal water conditions for these large fish.

The good news is, Iridescent sharks are known to be relatively hardy fish, capable of withstanding some less than ideal water parameters. So a few mistakes here and there probably won’t kill them (maybe). We’re here to prevent those mistakes however, and give your ‘sharks’ the best quality of life (next to nature). Thankfully, the water requirements for these fishes are very achievable. In fact, all their requirements are fairly easy and straightforward. Iridescent sharks would love a temperature range of 72°F-79°F, or 22°C-26°C. Keep the pH at neutral, around 6.5-7.5, and the hardness at 2-29 dH. Easy-peasy, nice and breezy. 

Typical Diseases

Diseases: grim business, but it must be addressed. Unfortunately, Iridescent sharks are not any more immune to illness than any other fish. In fact, for some ailments, the Iridescent shark can even be more vulnerable due to being scaleless. Iridescent sharks are mostly just susceptible to common fish diseases. Some of these typical ailments are:

  • Fish Ich or White Spot disease- This is a parasitic ‘skin infection’ that causes unbearable itch to your fish. They can end up scratching themselves on your tank ornaments and if left untreated, become lethargic and bloody. 
  • Fungal diseases- fish can become darker in color, lethargic, and swim in unnatural patterns. 
  • Bumps and scratches- While not a ‘disease’, it must still be noted that Iridescent sharks can attain injuries from swimming and bumping the glass walls of your tank. This can happen when they are stressed, scared, or the tank is just too small for them.

Fortunately there are a plethora of medications available in the market to treat these ailments. However, these aforementioned afflictions can also be easily prevented, if you keep a close eye on your beloved sharks. Keeping water conditions optimal at all times is a must to prevent fungal growths, and stressing out your aquatic friends. A stressed fish only becomes more vulnerable to disease, so keep their tanks clean, their waters ideal, and you’ll have no problem-o.

Tank Setup

For their tank needs, Iridescent sharks don’t really require much. When aquascaping, your best bet is to imitate the natural surroundings Iridescent sharks are used to, which are large rivers of Southeast Asia. This will help them feel less stressed and right at home. 

Just like in the wild, they appreciate a soft substrate and dim lighting. Go for soft aquatic soil instead of gravel or even sand substrates. Place a couple of large rocks and floating plants; this will not only help them feel  more secure, but will provide ample shade as well. Some plants such as Hornworts can also help decorate your tank and be a source of food for Iridescents. Try placing some and see how your aquatic friends like it.

It’s important to note that these catfishes are also incredibly messy. So perhaps it’s best to set up a powerful water filter to keep your tank clean. Last but not least, place your tank in a nice, peaceful area where there is not much traffic or noise. 

Tip: When decorating your tank, be careful not to cramp up their space. Iridescent sharks are large and active swimmers, so they won’t appreciate any more cramping in their environment.

Food & Diet

You’ll be glad to know that Iridescent sharks are indiscriminate eaters. Omnivorous with a healthy appetite, these giants will eat most anything you give them. In nature, they typically scarf down anything they can find with their whisker-like barbels. Don’t overfeed these shark-catfishes however, and settle for a feeding schedule of 2-3 times daily. 

Iridescent Shark suitable food includes:

  • High-quality flakes
  • Brine shrimps
  • Bloodworms
  • Small fishes (feeder fishes)
  • Insects and their larvae

Mating & Breeding Behavior

If you’re planning on breeding these gentle giants yourself, there is bad news in store. Iridescent sharks unfortunately cannot be bred in captivity. They are migratory fish that travel upstream in the spring to spawn. Naturally, this means they require specific environmental conditions to breed, which is just not feasible in a tank. 

Their sheer size also puts a crimp to any breeding attempts you might think of. They need massively large bodies of water to breed, and no home tank or pond can emulate that. 

Iridescent Shark Tank Mates

So now you’re thinking, these Iridescent sharks are big and intimidating, they probably like being alone. Wrong! While this fish can be a literal aquatic giant, they do not do well alone. In fact, they are pretty desperate for company and will become stressed and on edge without one.

These big babies are die-hard schooling fish. They do well with their own kind, traveling in Iridescent shark shoals. Being in a group makes them feel safe and secure (who doesn’t?). It doesn’t end with just fellow Iridescent sharks either-there are plenty of tank mate choices you can consider for your Iridescent shark. 

Tank Mates Compatible with Iridescent Shark are:

  • Peaceful fish of similar size
  • Other Iridescent sharks
  • Oscar fish
  • Bichir
  • Silver dollar
  • Large plecos
  • Tinfoil Barb

If you’re thinking of adding smaller-sized fish with the Iridescent shark you must be aware of the consequences. Smaller fish will end up as meals, so it’s best not to put any in with these freshwater sharks. Aggressive fishes are also a bad idea and will stress out your sharks, preventing them from living peaceful underwater lives.

Iridescent Shark Temperament & Behavior

Contrary to their name and appearance, Iridescent sharks are of a peaceful temperament. In fact, most would even describe them as extremely shy and skittish. They are nervous by nature and the slightest movements can frighten them. 

These sharks have very poor eyesight as well and mostly rely on just their barbels to grope for food debris and other things in the tank. This slight blindness can agitate even further their already panicky personality. When scared out of their wits, Iridescent sharks often swim in a frenzy and bump into the glass walls of the tank. This bumping and scratching can end up harming them and causing injury. And sometimes, these panic attacks can even result in your sharks sinking on the bottom tank, and just lying there until their alarm subsides. A bit dramatic.

Iridescent sharks are active daytime swimmers and desperately need a school of other Iridescents with them. Being with their own kind calms them down, so a school of around five Iridescent sharks would be perfect. As their owner, you could also do your part in helping them be at ease. Firstly, try to place your tank in  the quietest and peaceful part of your home. Secondly, when approaching your skittish friends, try to do so slowly and carefully. Don’t just run to and from the tank; doing so will absolutely give the poor sharks the fright of their lives. 

For you and your guests, it would do well to remember not to make any unnecessary noise or ruckus. Iridescent sharks are very sensitive, so they’re probably not the best choice for a chaotic household, and are more suited to those with a more relaxed lifestyle.

To End

Anything worth doing, is worth doing well. And that applies perfectly to keeping an Iridescent shark. While loads of fun to keep, this fish is not for everyone. Undoubtedly, a shoal of Iridescent sharks takes up a lot of space, and many fishkeepers can’t accommodate that. Iridescent sharks can get depressed when alone, so this is non-negotiable. They absolutely need to be in a group. 

If you are well-prepared and determined to have this shark-catfish however, you won’t ever regret it. They are some of the most beautiful fishes you can keep in an aquarium, with wonderfully amusing personalities.

Apart from their space requirements, Iridescent sharks are actually not hard to take care of. They’re not picky eaters, and are even tolerant of a few mistakes you might make along the way. These shark-catfishes are also naturally long-lived so they can be with you through a good many years if you treat them right. As a matter of fact, if space is not an issue and you’re looking for a longtime companion, the Iridescent shark is probably for you. 

Note: Please consider the environment before printing this Iridescent Shark care sheet.

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