Monday November 24, 2025
Bangkok Post —
A freshwater fish species long thought lost for 94 years has been rediscovered in Thailand, says nature and biodiversity group Siamensis.org.
The species, known locally as pla bu sua (Brachygobius sua), was found by Kaweewat Kaosasiwattanapong, 18, who lifted a small trap in a canal connected to the Mae Klong River and noticed unusual markings on the fish.
Unsure of its identity, Kaweewat posted photos to the Siamensis.org community page. The site administrator recognised the pattern as potentially belonging to B. sua, first described in 1931 by American ichthyologist Hugh M Smith. A second specimen was later collected at the site, alongside ordinary pla bu (B. sabanus) for comparison.
Photos were sent to expert Helen Larson, who confirmed the fish and described the rediscovery as “historic”.
The species was originally named Thaigobiella sua by Smith after being found in a Bangkok canal in 1931. A sample was sent to the Smithsonian National Museum of Natural History, but later went missing, leaving only Smith’s drawing and description. In his 1945 book The Fresh-water Fishes of Siam, or Thailand, Smith admitted errors in his earlier fin-ray counts.
Further confusion arose when a specimen collected in Malaysia in 1938 was considered the closest match to Smith’s description. With no confirmed samples, B. sua was eventually treated as a synonym of Brachygobius xanthozona.
Siamensis.org said the rediscovery ends decades of uncertainty and will allow proper documentation.