Farmed and captive fish show signs of boredom and chronic stress in barren environments. Environmental enrichment improves welfare and production outcomes.
The cognitive complexity of fish revealed by welfare research has implications for how we design farm environments. Fish in barren tanks develop stereotypic behaviour patterns similar to those seen in mammals in inadequate environments. Providing structural enrichment - substrate, objects, varied lighting, and flow patterns - reduces these behaviours and improves welfare indicators. Fish given choice tests show preferences that suggest they have positive experiences in certain environments. While enrichment in commercial aquaculture faces practical challenges, low-cost interventions such as substrate in rearing tanks show welfare benefits with minimal cost.