Research into environmental enrichment for farmed fish is revealing how structural complexity and variation can improve welfare by allowing more natural behavioral expression.
Fish enrichment research represents the frontier of aquaculture welfare science. The evidence that farmed fish benefit from environmental complexity is growing: structural enrichment that provides cover, substrate variation, and spatial complexity reduces aggression, creates more uniform size distributions that improve growth efficiency, and allows expression of natural habitat-seeking behaviors. The challenge is translating research findings into commercially scalable systems. Net pens that provide minimal structural enrichment because they are designed for production efficiency rather than behavioral welfare may be improvable through relatively simple modifications. The welfare case for fish enrichment rests on the same foundation as terrestrial animal enrichment: animals have behavioral needs shaped by their natural history that barren environments fail to meet.