Iridescent shark care guide

Iridescent shark (Pangasianodon hypophthalmus) is a large freshwater fish that resembles a shark in some way, which if fact is the reason why the fish is called so. In South-East Asia this fish is grown to cook it, but in the USA and Europe this fish is often kept in tanks. Further in the article, you’ll find out how to keep iridescent shark fish, feed it, select tank mates, and breed it.

Habitat in the wild

The iridescent shark inhabits in Mekong, Mae Klong and Chao Phraya river basins in the territory of Thailand, Vietnam, Laos and Cambodia. The fish is also bred in the USA (in the paddy fields), Bangladesh, Singapore and Philippines.

The pangasius shark is encountered in large rivers with sandy or rocky bottoms; it swims in the middle water layers. It breathes using its gills and due to special structure of its air-bladder. The fish is quite active and timid at the same time; if it feels danger it pretends to be dead.

Similar to other Pangasianodon kind representatives, this is an anadromous species that performs long-distance migration. It travels thousands of kilometers from its spawning areas that are located upstream to the places where it feeds and where its juveniles grow in the lower reaches of a river.

This species is an omnivorous one, it feeds on algae, seed plants, zooplankton and insects. Adult species also eat fruit, crustaceans and fish.

Scientific NamePangasianodon hypophthalmus
Common NamesIridescent shark; pangasius shark; hammerhead fish pet; iridescent fish; id shark
Ease of keepingEasy
Lifespan20 years and more
Tank size220 gallons and more
Tank typeCommunity of large fishes
Temperature22–30 °C (72–86 °F)
Water hardness9–20 dGH
SizeUp to 130 cm (4.3 ft)


Iridescent shark is a large freshwater fish. It can be up to 130 cm (4.3 ft) long and weigh 44 kilos (97.0 lb). The lifespan is more than 20 years.

The juveniles are especially attractive, they have two wide stripes that stretch all over the body. However, the adult species have paler coloring and the stripes disappear. Their body coloring becomes uniformly gray and the fins are dark. The abdomen and the mouth are silvery colored. You may also encounter albinotic species of the fish on sale.

The fins are dark gray with silvery edging, anal and tail fins have dark stripes. The head and eyes are large. The fish has two pairs of barbels like those of a catfish.

Difficulties in keeping

Though the iridescent shark is quite undemanding one, still before buying it you’d better think twice. The thing is that for the adult species you will need a really huge tank.

The idea of keeping iridescent shark in a tank still stirs up controversy. Though in captivity this fish very seldom reaches the size it can be in the wild, but yet it grows to be rather large (up to 20 inches long). At that the tank size doesn’t influence their growth rate.

The iridescent shark is peaceful enough, but only towards tank mates that it can’t eat. Tank water parameters are of no significance for the fish, but the water has to be clean. Pangasius shark will everything you give to it.

The iridescent shark is a very timid one and considering its size it is quite capable to break the tank wall if it panics. Iridescent shark has very soft skin that can be easily damaged, therefore you should remove all sharp objects from the tank.

Keeping in a tank

Tank size

On sale you may often see juveniles – they are small and attractive, which makes buyers interested. However, the sellers don’t say how large the fish can grow. Iridescent shark becomes extremely large and it requires proper sized tanks. Besides this fish prefers living in a school and it means that far more space in a tank is required.

For the juveniles a tank of 400 liters (88 gallons) capacity is required, for the adult fish – from 1000 liters (220 gallons). Another thing is that pangasius shark is very active and it needs a lot of space to swim and it has to be kept only in a school of its kind.

The fish feels comfortable in a school of at least 5 species, can you imagine how huge the tank should be? Well, if you after all decided to have iridescent shark as a pet, then…

Tank decor

The tank is desirable to have oblong shape – the fish is very active and spry, they need a lot of room to swim.

Put coarse sand on the tank bottom, you may also add some live tank plants (you should fix them tightly to the bottom or put in small flower pots and dig into the substrate). Also it is desirable to put some decorations in the tank, for example, stones, snags or shelters of unusual spape.

However, be careful with the latter, since iridescent shark unlike other fishes isn’t covered with protective bony plates, which means that its skin is quite thin an it is easily damaged. Therefore, choose decorations that can’t hurt the fish.

Be careful! Iridescent shark has very poor eyesight, it is a very nervous fish easily scared. Don’t knock on the tank glass, the fish may hurt itself while its crazy panic attack. Frightened fishes hysterically rushes all around the tank hitting the glass walls, decorations and other fishes.

After the panic attack is over you may see the fish lying on the tank bottom beaten and limpen. If you are lucky, the fish will recover in time.

Water parameters

Tank water parameters may vary, the main thing is that the water is clean. Water temperature should be from 22 to 26 °C (71,6-78,8 °F). A powerful canister filter is a must, weekly water renew up to 30% of the total tank volume, since the fish produces a huge amount of organic waste.


Is an omnivorous fish, it is famous for this feature – it will eat everything it finds. It is gluttonous as well. In a tank it eats all types of food – live, frozen, flakes, tablets. Mixed feeding is the best idea for diet – combine vegetable and live components.

Feed the iridescent shark twice or three times a day, but with portions it can eat in 5 minutes. As for the protein food, it’s better to feed the fish with prawns, bloodworm, small fishes, worms, crickets. As for the plant food, give it squash, cucumbers, lettuce leaves.

Tank mates

The iridescent shark juveniles stay in a school, but the older the fish becomes the more it tends to stay alone. Iridescent shark gets alone well with tank mates of the same size or the fishes they can’t swallow. Pangasius shark will treat any small fishes as food.

It may disturb slow species or vice versa it can be scared by aggressive and predatory tank mates.

As a rule, is kept with large and moderately aggressive cichlids (Texas cichlid, Salvin’s cichlid), large catfishes (sailfin pleco, common pleco), bottom-lying fish (bichir, fire eel).

Gender differences: male vs female

The iridescent shark female is larger and fatter than males and it has a bit lighter coloring.


Breeding the iridescent shark in captivity is very seldom the case due to the size and requirements to the spawning tank. In the wild pangasius migrates downstream to its spawning grounds, it happens in late spring or early summer. Such conditions can’t be simulated in a home aquaria. Usually, the fish is bred in huge ponds of Asian fish hatcheries, since only Vietnam exports Pangasius hypophthalmus to more than 80 countries.