Flounder and flatfish are increasingly farmed in East Asia, with specific welfare considerations arising from their benthic lifestyle and sensitivity to crowding and substrate conditions.
Flounder welfare in aquaculture requires attention to their benthic lifestyle and territorial nature. Tank design must prioritise floor area over depth — flounder spend most of their time resting on the bottom and cannot use water column space. Overcrowding the floor area causes territorial aggression, resulting in biting injuries, particularly to fins and eyes. Summer heat stress in tanks without adequate cooling causes physiological stress and mortality. Grading juvenile flounder to separate size classes reduces cannibalism but involves handling stress. Substrate provision — sand or gravel on tank floors — allows natural burying behaviour that reduces stress and aggression. Welfare-conscious flounder operations prioritise appropriate floor density, substrate, and water temperature management.