The Mekong giant catfish, Latin name Pangasianodon gigas or in Thai ปลาบึก (plaa buek) is one of the largest freshwater fish in the world. They are native to the Mekong river and live on algae and plankton, they do not have any teeth but have rough pads in their mouths instead. The heaviest recorded specimen was a 293kg female netted in the Mekong river in the Chiang Khong district of Chiang Rai, Northern Thailand in 2005. The wild population of Mekong giant catfish is critically endangered, fishing for wild Mekongs is illegal in Thailand. Mekongs are now bred in captivity and sold to fishing parks as part of a conservation programme.
The current IGFA world record for rod caught fish stands at 117.93kg, the catfish was caught at a fishing park in Southern Thailand, see Retired British Navy Captain Catches 260-Pound World Record Mekong Giant Catfish for more details. This record is unlikely to be broken as IGFA rules now state “No applications will be accepted for fish caught in hatchery waters, sanctuaries or small bodies of water that are stocked with fish for commercial purposes.” More information about the Mekong giant catfish can be found on Wikipedia.
In the Pattaya area Mekong catfish are stocked at Baetong Fishing Park, Pattaya Fishing Park and Jomtien Fishing Park. For your best chance of a really big Mekong try Bungsamran in Bangkok, they claim they have Mekong catfish in excess of 330lb.