Pangasianodon hypophthalmus
Pangasianodon hypophthalmus
(iridescent shark)
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Pangasianodon hypophthalmus (Sauvage, 1878)

Common name: iridescent shark

Synonyms and Other Names: Pangasius hypophthalmus (Sauvage, 1878), Pangasius sutchi Fowler, 1937; tra, swai, striped catfish, sutchi catfish

Taxonomy: available through www.itis.govITIS logo

Identification: Pangasianodon hypophthalmus is similar in body shape to blue (Ictalurus furcatus) and channel catfish (I. punctatus), but can be generally distinguished by the number of pairs of barbels around the mouth: P. hypophthalmus has only two pairs of maxillary barbels (at the corner of the mouth), whereas Ictalurus spp. have four pairs of barbels including chin (below the mouth) and nasal (above the mouth) barbels.

Size: 130 cm SL.

Native Range: Southeast Asia; Mekong and Chao Phraya rivers and Maeklong basins (Van Zalinge et al. 2002). Introduced into additional river basins for aquaculture (Roberts and Vidthayanon 1991).

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Nonindigenous Occurrences: This species was reported in 1988 from a Florida creek that drains into the Hillsborough River near Tampa (Shafland et al. 2008, as Platytropius siamensis), and from a non-specific location circa 1999 (P. Shafland, personal communication). In 2017, a specimen was captured by commercial fisherman in the Illinois River near Naplate, Illinois (K. Irons, pers. comm.).

Ecology: Inhabits main channels of large rivers, moving to floodplains and marshy areas during flooding in the rainy season. Omnivorous, primarily feeding on algae, zooplankton, crustaceans, and fishes. Large migratory spawner, capable of long distance movements (>300 km) upstream in major rivers in Southeast Asia to spawning areas in northeastern Cambodia (Vidthayanon and Hogan 2011; Van Zalinge et al. 2002).

Means of Introduction: Unknown. Likely aquarium release as it is common in the trade.

Status: Unknown; likely failed.

Impact of Introduction: Unknown, but likely none due to failure of introduction.

Remarks: Shafland et al. (2008) report the capture of five "false Siamese shark" (identified as Platytropius siamensis), stating that it is a common aquarium fish. However, this species has not been observed in the wild since the mid-1970s and is currently classified as extinct (Ng 2011), and thus was likely not common in the aquarium trade in 1988. This is likely a case of misidentified individuals of Pangasiodon hypophthalmus, which is commonly found in the aquarium trade, and the report of Shafland et al. (2008) is included here.

Farmed widely as a food fish in Asia, and sold in the U.S. as swai. Wild stocks have generally declined since the 1980s due to overexploitation (Vidthayanon and Hogan 2011). A related species, Pangasius bocourti, is also used in aquaculture and is marketed as basa.

References: (click for full references)

Ng, H.H. 2011. Platytropius siamensis. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2., visited on 28 February 2013.

Roberts, T.R. and C. Vidthayanon, 1991. Systematic revision of the Asian catfish family Pangasiidae, with biological observations and descriptions of three new species. Proceedings of the Academy of Natural Sciences of Philadelphia 143:97-144.

Shafland, P.L., K.B. Gestring, and M.S. Stanford. 2008. Florida's exotic freshwater fishes - 2007. Florida Scientist 71(3):220-245.

Van Zalinge, N., L. Sopha, N. Peng Bun, H. Kong, and J.Valbo-Jørgensen. 2002. Status of the Mekong Pangasianodon hypophthalmus resources, with special reference to the stock shared between Cambodia and Viet Nam. MRC Technical Paper No. 1, Mekong River Commission, Phnom Penh.

Vidthayanon, C., and Z. Hogan. 2011. Pangasianodon hypophthalmus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1., visited on 10 September 2012.

FishBase Summary

Author: Neilson, M.E., Loftus, W.F., and Benson, A.

Revision Date: 11/28/2017

Peer Review Date: 2/10/2016

Citation Information:
Neilson, M.E., Loftus, W.F., and Benson, A., 2018, Pangasianodon hypophthalmus (Sauvage, 1878): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL,, Revision Date: 11/28/2017, Peer Review Date: 2/10/2016, Access Date: 3/24/2018

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

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Page Last Modified: Wednesday, March 14, 2018


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Citation information: U.S. Geological Survey. [2018]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [3/24/2018].

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