Hypsibarbus wetmorei

Hypsibarbus wetmorei, the golden belly barb, lemon fin barb, lemon barb or Kerai is a species of cyprinid fish. It is native to the Mae Klong, Mekong, Chao Phraya, Tapi and Pahang rivers in Mainland Southeast Asia. Although locally common and considered to be a species of Least Concern, it is threatened by overfishing, dams and pollution. It typically reaches in length, but has been recorded up to about.
It is popular both as a food fish and as an ornamental species, particularly in shorter-than-normal forms known as "balloon" or "Pla San". In the ornamental fish trade, it is often kept as a tank mate with larger fish such as arowanas. In Thailand, it is vernacularly known as Pla Tapak, Pla Tapak Lueng, Pla Tapak Thong, or Pla Krapak, as mentioned in King Rama V's poem Journey to Sai Yok.
Artificial insemination has been carried out by the Kamphaeng Phet Inland Fisheries Research and Development Center since 2010, with fry released into natural water bodies for conservation purposes.