The dwarf chain loach, (Ambastaia sidthimunki) is a freshwater fish belonging to the family Botiidae. This species is endemic to the Mae Klong basin (including Khwae Noi River) in Thailand, and the Ataran River on the Thai-Myanmar border. It was thought to be extinct in the wild until recently rediscovered in Sangkhla Buri. While they disappeared from the wild, it remained in the aquarium trade because of artificial breeding by private fish farms for over three decades.
The dwarf chain loach can grow up to 2.5 inches in length. It prefers water with temperature 77 to 86 °F, pH 6.5 to 6.9 dGH to 8.0. It is omnivorous, with a diet including live crustaceans, insects, snails, etc.
This loach closely resembles Ambastaia nigrolineata, another Thai protected species, especially when the fish is fully grown. The difference is easily seen when the fish is still small. Juveniles of A. sidthimunki have dotted patterns while A. nigrolineata have horizontal lines on them. Furthermore, the chain pattern of A. sidthimunki develops in fish at a smaller size.