The iridescent shark, also known as the iridescent catfish, or by its binomial nomenclature, Pangasius hypophthalmus, is a species of freshwater fish known for its large size and shark-like appearance.
Iridescent sharks definitely aren’t recommended for beginners, partly because of the sheer amount of space required to keep these fish healthy and happy.
But if you’re an experienced aquarist, you might be considering taking on the care of this incredible species.
Assuming that you have the knowledge as well as the time and money on your hands to give an iridescent shark a good life, this is the care guide for you.
We’ll be explaining everything you need to know to look after these fish, from what they eat to which other species they can live with.
If you want to become an iridescent shark expert, read on!
An Introduction To Iridescent Sharks
The iridescent shark species (Pangasius hypophthalmus) might sound scary due to the (somewhat unfair) deadly reputation of sharks, but it’s important to note that these fish are not actually sharks.
If you look up lists of freshwater sharks, you’ll find that the iridescent shark is included every time.
Technically, though, they are part of a fish family called Pangasiidae, which is made up of shark catfish.
The iridescent shark is native to bodies of freshwater in Southeast Asia. They are most commonly found in wide, spacious rivers and feel most comfortable in deeper waters.
The largest populations of iridescent sharks can be found in the Chao Phraya and Mekong rivers.
Scientists believe that the sharks prefer these specific rivers because they are so large that the fish can easily migrate with the changing of seasons.
While iridescent sharks are often caught and sold at low prices for food, more and more aquarists are purchasing these catfish as aquarium fish.
Identifying An Iridescent Shark
In order to correctly identify an iridescent shark and distinguish it from other, similar-looking species, you need to look at the following:
Luckily, iridescent sharks have fairly unique physical characteristics which make them quite easy to identify.
The iridescent shark has a snail-shaped dorsal fin protruding from its back, much like a real shark.
These fish will cleverly reposition their dorsal fins to help them move through the water depending on which swimming style they adopt.
Iridescent sharks have caudal fins that resemble the dorsal fin in terms of skin texture, and they also have anal fins that begin around half-way down the belly and extend all the way to the caudal peduncle (where the body tapers, level with the caudal fin).
An iridescent shark will also have barbels near its mouth. Barbels are the whisker-like tendrils that can be seen in most species of catfish.
These are sensory organs and they help the fish to detect its prey and move around in dark water.
If you look at the eyes of an iridescent shark, you’ll notice that they’re on the larger side.
This will be especially obvious in juveniles because their smaller size makes their eyes look larger, proportionally.
One of the reasons this shark catfish species is often simply referred to as a shark is because of its size.
The average iridescent shark is between 3 and 4 feet in length. It’s so important to understand what 4 feet actually looks like before you take on an iridescent shark as an aquarium fish.
Time and time again, we see well-meaning aquarists who have brought home an iridescent shark without anticipating its full size.
This often leads to inadvertent cruelty because the fish ends up cramped in a tank that isn’t large enough to meet its needs.
You can also use the size of an iridescent catfish to determine whether it’s male or female.
The males and females of this species don’t really differ in length, but the males have more streamlined bodies while the females are noticeably wider.
Most iridescent sharks start their lives with shiny, dark skin.
As they grow, their skin lightens and becomes more clearly gray compared to its original, almost-black color. The skin also develops more of a matte texture.
The only exception to this rule is the albino iridescent sharks.
Albino iridescent sharks are rare, but there is quite a high demand for this color variation, which is totally white with bright red eyes.
Average Iridescent Shark Lifespan
Taking on an iridescent shark is quite the commitment because these fish live for over 20 years on average.
Obviously, two decades is a long time to commit to any pet – it’s longer than the average lifespan of most cats and dogs, for example.
But if you’re going to get iridescent sharks for your aquarium, it’s important that you feel able to look after them throughout their lives and keep them in good enough health to reach their full expected lifespan.
If 20 years feels like too much of a commitment, that’s understandable, but in that case, please look for a different fish species that has a shorter life expectancy.
Iridescent Shark Temperament
Many people associate the word ‘shark’ with aggression and a bloodthirsty nature.
While this isn’t even an accurate representation of the average shark’s temperament, the words ‘iridescent shark’ might conjure up similar assumptions.
Despite the potential for misconceptions, iridescent sharks are actually very calm. They don’t usually display aggressive behaviors towards other fish.
You might see them making sudden movements and splashing in the tank, which can be alarming due to their large size, but this behavior is linked to nervousness rather than aggression.
With that being said, in order to maintain your iridescent shark’s naturally peaceful temperament, you’ll need to make sure that they are kept in the right conditions.
For example, iridescent sharks are predisposed to living in schools of the same species.
If you don’t provide your iridescent shark with other iridescent catfish tank mates (more on this later), you might find that they are more likely to act out nervously.
Caring For Iridescent Sharks
We’ve now covered all the basics you need to know about iridescent sharks. However, if your goal is to care for these fish yourself, you’ll need more in-depth knowledge about how to look after them.
If this is the information you’ve been looking for, keep reading!
Optimal Tank Size
One of the most important aspects of housing iridescent sharks is keeping them in a large enough tank.
Iridescent sharks don’t reach their full, adult size for several years.
At one year old, iridescent sharks are usually only about a foot long. If you get a juvenile iridescent shark, please don’t base the size of the tank on the fish’s current size.
When purchasing a tank of an iridescent shark, you should assume that the fish will reach the maximum size of 4 feet.
For a full-size iridescent shark, you will need a tank that holds 300 gallons of water at an absolute minimum.
Some aquarists who keep larger fish choose to house younger fish in smaller tanks temporarily before eventually transitioning the fish to a bigger tank.
However, we don’t recommend this because by the time you realize that your fish is getting too big for its tank, the fish will probably have already begun to experience the negative effects of a cramped living space.
If you’re going to start with a smaller tank for a juvenile iridescent shark, please make sure that you get a larger tank before your fish actually needs one.
It’s also important to note that the 300-gallon estimate is the correct amount of space for just one iridescent shark.
However, we would never recommend housing a single iridescent shark by itself as this can have negative effects on its health and temperament, as we’ll explain in more detail later.
Each additional iridescent shark you add to your tank will need another 300 gallons of water to itself.
Like most fish, iridescent sharks can benefit from a few additions to their tanks that help to recreate their natural habitat.
Because iridescent sharks usually live in rivers, additions like rocks and driftwood are a good idea. This will make your fish feel like they are swimming around a river bed.
Iridescent sharks aren’t used to having a lot of plant matter in their environments, so you don’t need to worry about incorporating any plant life.
If you are going to decorate your iridescent shark tank, however, please take care not to over decorate.
Keep decorations confined to the bottom of the tank and ensure that they don’t take up the space that your fish need to move around comfortably.
If you don’t provide iridescent sharks with the correct water conditions, they can quickly begin to get sick and their lifespan will reduce significantly despite their natural hardiness.
Therefore, it’s really important to have the right tools in place to monitor the water in the tank.
Iridescent sharks need water temperatures no higher than 79°F and no lower than 72°F.
It’s best to have a water thermometer attached to the wall of your tank to make sure the temperature doesn’t deviate from this range.
The pH of the water should be roughly neutral, with the acceptable range falling between 6.5 and 7.5.
You will also need to pay attention to the hardness of the water in the tank. Anywhere from 2 dGH to 20 dGH is suitable for iridescent sharks.
Iridescent Shark Diet
Of course, if you’re going to keep iridescent sharks, you’ll need to know what they eat!
The first thing that you should know is that iridescent sharks are omnivorous, meaning that their optimal diet consists of a combination of meat-based protein and plant matter.
It’s also worth remembering that iridescent sharks are catfish, and catfish are notoriously not fussy eaters.
However, this doesn’t mean that you shouldn’t put any thought into your iridescent shark’s diet.
You need to ensure that your pet is getting all the micronutrients it needs to stay healthy, and this involves creating a diet that consists of the perfect combination of foods.
The first thing you should incorporate into your iridescent shark’s feeding schedule is flake food from a reputable company.
Flakes are specifically formulated to give fish the base nutrition that they need.
However, if you want your fish to truly thrive, it’s best to incorporate some live protein sources.
Iridescent sharks especially enjoy and benefit from the nutrients in bloodworms, feeder fish, brine shrimp, and worms.
Feeding your iridescent sharks these foods in the correct quantities (this will vary depending on the development stage your fish is currently in) will not only improve their nutrition but also allow them to engage in their natural prey-hunting behavior.
Again, just like the fish flakes, any live food you introduce to your iridescent shark’s tank should be purchased from reputable sellers and be of the highest possible quality.
Live feed that is low in quality can introduce diseases into the water which will impact the health of your fish.
Iridescent sharks don’t suffer from any diseases that can be considered specific to their species. However, this doesn’t mean they can’t be prone to certain illnesses.
One thing to be aware of is that iridescent sharks don’t have scales. Scales serve a purpose, which is to protect the skin underneath.
This lack of scales means that iridescent catfish don’t have the same protection against skin diseases.
If iridescent sharks are exposed to the Ichthyophthirius multifiliis parasite, they may develop a skin condition commonly known as Ich.
Luckily, this is a treatable condition, and the color of the iridescent shark’s skin means that you’ll be able to notice it early.
You can greatly minimize the risk of your iridescent shark getting sick if you regularly check that all of the water parameters outlined in the ‘water conditions’ section on this article are within the recommended ranges.
Potential Tank Mates
We mentioned earlier that we don’t recommend keeping an iridescent shark in a tank by itself. That’s because iridescent sharks in the wild typically live and travel in schools.
Housing a lone iridescent shark can lead to an increase in anxious behavior because these fish are not accustomed to life outside of a school.
This means that if you’re going to choose any tank mate for your iridescent shark, the best choice would be other iridescent sharks.
Ideally, you should keep iridescent sharks in groups of 4 at a minimum. This is the best way to ensure that your fish are happy, which should be your priority as an aquarist.
With that being said, iridescent sharks can also live with fish of other species.
You just need to make sure that the other fish are not significantly smaller than the iridescent shark so they don’t get mistaken for prey.
Some examples of fish you could introduce as tank mates for an iridescent shark include black sharks, silver dollar fish, tinfoil barbs, large plecos, oscar fish, and bichir.
Whenever you introduce a new fish to your tank, pay attention to the interactions so that you can step in if necessary.
Breeding Iridescent Sharks
If you’re planning on getting some iridescent sharks so that you can breed them, you might need to change your plans because iridescent sharks can only be bred in the wild.
This is because the mating instinct in iridescent sharks is closely linked to their instinct to migrate.
Migration, for iridescent sharks, involves covering pretty huge distances, and this can’t be done in the confines of even the largest tank.
Caring for iridescent sharks comes with significant expenditure and commitment.
If you’re not prepared to keep at least 4 of these fish in an aquarium of at least 1,200 gallons, and if you don’t think you can make a 20-year commitment, this isn’t the fish for you.
However, if you have a lot of experience as an aquarist and, having read this guide from start to finish, feel capable of the task, congratulations!
You’re the perfect iridescent shark owner. Good luck with your new aquarium inhabitants!
- How To Grow And Decorate With Hornwort (Ceratophyllum): Planting, Propagation, Care - June 20, 2022
- How To Care For Cabomba (Cabomba Caroliniana): Planting, Propagation, Care & More - June 20, 2022
- How To Succeed With Your New Red-tail Catfish (Phractocephalus): Diet, Feeding, Breeding & More - June 20, 2022