The Iridescent Shark is not a true shark, but a highly active, schooling catfish native to Southeast Asia. While frequently sold as tiny juveniles, they are notorious 'tank busters' that grow to massive sizes. They are extremely skittish and easily spooked, often injuring themselves by crashing into aquarium glass. They are best suited for heated indoor ponds or massive custom aquariums.
At a Glance
Tank Requirements
Water Parameters
Temperament & Compatibility
Available Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard Adult
Fully grown adult form. Requires a massive footprint as they are continuous, fast swimmers that startle easily and have a very high bioload.
Same care requirements as the base species
Also known as: Wild Type, Regular
Juvenile (Grow-out)
Typical size sold in pet stores. They are schooling fish at this age but will grow incredibly fast. Purchasing them without a concrete plan for a 500+ gallon upgrade is strongly discouraged.
Differs in 3 traits from base species
Also known as: Baby Id Shark, Small Pangasius
Albino Adult
A common color morph lacking pigment, resulting in a white/pink body and red eyes. Has the exact same massive size, skittish behavior, and care requirements as the standard type.
Same care requirements as the base species
Also known as: Albino Id Shark, White Pangasius
Iridescent Shark Care Guide Summary
The Iridescent Shark, scientifically known as Pangasianodon hypophthalmus, belongs to the Catfish family group. Adults reach a maximum size of approximately 100 cm and have a fusiform body shape with a fast growth rate. Classified as mostly peaceful, this species primarily occupies the mid-level zone of the aquarium and produces a extreme level of biological waste.
To thrive, the Iridescent Shark requires a freshwater only aquarium with a minimum volume of 2000 litres and a tank length of at least 250 cm. Water temperature should be maintained between 22°C and 28°C, with a pH range of 6.5–7.5 and a general hardness of 2–20 dGH. A moderate water flow is preferred.
The Iridescent Shark is a rewarding species to keep, provided its core environmental needs are met. This species is available in 3 varieties: Standard Adult, Juvenile (Grow-out), and Albino Adult. Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Iridescent Shark Habitat Setup
When setting up an aquarium for the Iridescent Shark, a moderate water flow best suits their natural preferences. Because this species occupies the mid-level zone, the aquarium layout should prioritise open swimming space in the centre of the tank for free movement. Useful additions include smooth gravel or rounded substrate to protect their sensitive barbels. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Iridescent Shark Compatibility Notes
Classified as mostly peaceful, the Iridescent Shark is adaptable and can be kept singly or in a small group, offering flexibility when planning a community tank. When choosing tankmates, any fish small enough to fit in its mouth will likely be eaten. Selecting tankmates that favour different water layers from the mid-level zone can help reduce competition and territorial overlap.
Frequently Asked Questions About Iridescent Shark
How big does Iridescent Shark get?+
What tank size does Iridescent Shark need?+
What water parameters does Iridescent Shark need?+
Is Iridescent Shark peaceful or aggressive?+
Can Iridescent Shark live alone?+
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Does Iridescent Shark need a lid on the tank?+
Similar Species
Pictus Catfish
Pimelodus pictus
An extremely active, striking silver catfish with black spots and incredibly long barbels, native to South America. While peaceful toward similarly sized tank mates, they are highly effective nocturnal predators that will easily swallow small fish (like Neon Tetras) whole. They are scaleless and possess sharp pectoral spines that can easily become entangled in aquarium nets.
Clown Knifefish
Chitala ornata
A massive, nocturnal predator native to Southeast Asia, widely known for the distinct row of ocellated spots above its anal fin. While sold as small silvery cute juveniles, they grow incredibly fast into nearly 1-meter giants that require immense aquariums. They are obligate carnivores and will eat any fish small enough to fit in their large mouths. They are shy during the day and require large hiding tubes or caves.
Red-Tail Catfish
Phractocephalus hemioliopterus
A massive, fast-growing predatory catfish from the Amazon basin. Famous for its voracious appetite, bulldozer-like behavior, and distinct red caudal fin. Due to its enormous adult size (often exceeding 4 feet), it is strictly a 'monster fish' that requires a heated indoor pond or a colossal custom aquarium. It is highly predatory and will swallow absolutely any tank mate that can fit into its cavernous mouth.
Glass Catfish
Kryptopterus vitreolus
A highly unique, completely transparent catfish from Thailand. Unlike most catfish, they are mid-water swimmers that require being kept in schools to feel secure. They are incredibly peaceful and easily outcompeted for food. They require stable water parameters and dim lighting or shaded areas provided by floating plants.
Rainbow Shark
Epalzeorhynchos frenatum
A popular, active freshwater 'shark' (actually a cyprinid) known for its striking red fins contrasting with a dark or albino body. They are highly territorial bottom-dwellers. Only keep one per tank, as they are notoriously aggressive toward their own kind, other 'sharks' (like the Red Tail Shark), and similar-looking bottom feeders.
Otocinclus
Otocinclus vittatus
A small, peaceful, and highly popular algae-eating catfish native to South America. They are obligate shoaling fish that thrive in mature, heavily planted aquariums with steady water parameters and a constant supply of soft green algae and biofilm. They are extremely sensitive to uncycled or pristine/new tanks without natural food sources.