Various flounder species are farmed and wild-caught globally. As flatfish with benthic lifestyles, they have specific welfare needs distinct from pelagic farmed species.
Flounder welfare in aquaculture is constrained by the conflict between species behavioral needs and efficient tank system design. As obligate benthic fish that spend most of their lives resting on the substrate, flounder require flat-bottomed tank designs with adequate floor area per fish. Standard circular or raceway tanks used for salmonid aquaculture are poorly suited to flounder behavioral needs, and crowding of fish on inadequate floor area causes chronic social stress and physical damage.
The high rates of albinism (failure to develop normal dorsal pigmentation) in farmed flounder are welfare indicators — this condition correlates with suboptimal larval rearing conditions including light stress and nutritional deficiency. Albino flounder are penalized in markets but the welfare significance is that the condition reflects inadequate larval welfare conditions.