Thousands of glass and plastic bottles lie across the floor of Tran Ngoc Thang's farm in Hanoi, each one home to an aggressive, brightly coloured fish that must be raised alone.
Thang has been breeding Siamese fighting fish, also known as betta fish, for more than 20 years in Vietnam -- and his business is going swimmingly.
They were once prized for their combative nature and were pitted against each other in fights, with bets placed on which fish would triumph.
Now they are mostly kept for ornamental purposes but are still kept apart on Thang's fish farm to avoid any clashes.