Siamese Giant Catfish

The Siamese Giant Catfish is a commercially selected strain of Pangasianodon hypophthalmus developed through selective breeding programmes in Thailand and Vietnam to maximise growth rate and ultimate body size. It achieves 150 cm in captivity significantly faster than the wild-type Iridescent Shark, making it the preferred choice for public aquaria and large display pond operators seeking maximum visual impact. Like the parent species, it is silvery with a large forked tail and schooling behaviour.

In husbandry, requirements are essentially identical to the wild-type P. hypophthalmus but scaled up — the faster growth rate means tanks must be enlarged or fish transferred to larger systems more frequently. The same skittish tendencies require low-light, soft-substrate, padded-corner setups. Powerful filtration is even more important given the accelerated growth and correspondingly larger waste output.

This strain is rarely available outside Southeast Asian trade channels and specialist large-fish importers. Its primary market is public aquaria and indoor ponds rather than the conventional aquarium trade. Keepers interested in the Iridescent Shark should consider whether the wild-type or this selected strain best suits their long-term infrastructure plans.

Water: 22–28°C, pH 6.5–7.5, moderate hardness; very high volume water changes weekly. Tank: 5 000 L minimum; padded corners; very low lighting; extremely strong filtration. Feeding: Large sinking pellets, earthworms, blanched vegetables; fast metabolism requires regular feeding. Breeding: Hormonal induction only; not achievable in home settings. Compatibility: Peaceful but large; keep with similarly large fast-moving species only.