Iridescent shark (Pangasianodon hypophthalmus) care guide

Group
Freshwater fish
Other names
Iridescent shark catfish, Striped catfish, Sutchi catfish, Siamese shark, Pla sawai, Pangasius, Pangasius hypophthalmus, Pangasius sutchi
Family
Pangasiidae (shark catfishes)
Origin
Mekong, Chao Phraya and Maeklong basins in Thailand, Laos, Cambodia and Vietnam; widely introduced elsewhere for fish farming.
Water
freshwater
Maximum size
130 cm
Temperature
22–26°C
pH
6.5–7.5
Hardness
Soft to hard, 2–29 dGH
Minimum tank
5000 litres
Care level
expert
Temperament
peaceful

Care

The iridescent shark is sold in huge numbers as small, shiny striped juveniles, but it is a migratory river fish that reaches around 130 cm and 40 kg or more. PlanetCatfish calls it a classic "tank buster": very few home aquariums can house an adult. A tank of several thousand litres is the realistic minimum for one adult (our estimate of 5,000 litres; the sources give no figure), and many keepers end up needing a pond-sized system. Do not buy one unless you can provide this long term. It is a nervous, open-water shoaling fish that panics easily and can injure itself by crashing into the glass. Keep furnishings to a minimum to give swimming room, use a tight lid, avoid sudden movement and lighting changes, and add floating plants, which PlanetCatfish says reduce its skittishness. Strong filtration and frequent large water changes are needed for such a big, heavy-feeding fish. Aim for about 22–26 °C and pH 6.5–7.5; it tolerates a wide range of hardness. Young fish are silvery with dark stripes; adults lose the stripes and become uniformly grey. An albino form is also common. PlanetCatfish notes that males have darker stripes and are more slender than females, though it is unclear at what age this shows. In the wild it is listed as Endangered by the IUCN (2011), even though it is one of the most heavily farmed fish in the world and is sold as a food fish ("pangasius"). All aquarium stock is farm-bred. Selling: our policies require the adult size and long-term tank needs to be stated clearly in the listing. Large fish must travel by a specialist live-animal courier (see the Livestock shipping guide). Sources: PlanetCatfish (planetcatfish.com/common/species.php?speciesid=172); FishBase (fishbase.se/summary/Pangasianodon-hypophthalmus.html). Checked October 2026.

Diet

An omnivore. Young fish are more carnivorous: start them on bloodworm and catfish tablets, then move on to shrimp and vegetable foods such as spinach. PlanetCatfish says adults do best on mainly vegetable-based floating pellets. Do not overfeed, as growth is very fast.

Breeding

PlanetCatfish describes aquarium breeding as unknown and probably impossible. In the wild it migrates upstream to spawn in the Mekong between about May and August. Aquarium stock is produced commercially in large ponds.

Compatibility and tank mates

Peaceful, and will live with smaller fish, but its extreme nervousness and eventual size limit the choice. PlanetCatfish suggests large active fish such as bigger barbs, Labeo "sharks", large plecos and pacu. Any fish small enough to fit in an adult's mouth may be eaten. Best kept in a group in a very large system.

Last updated 5 October 2026. Community-edited care guide on Aquatic-Auctions.

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