Brown trout, rainbow trout, and grayling are prized by fly anglers and widely farmed. Their welfare in both contexts is important and increasingly studied.
Rainbow trout were central to key studies demonstrating fish pain responses — including research showing they rub injuries against gravel after painful stimuli, consistent with pain-motivated behaviour. Fly-caught trout experience hook penetration and fight stress; while catch-and-release is standard in quality fly fishing, improper handling (dry hands, prolonged air exposure) causes mortality and disease. In aquaculture, trout are among the better-studied farmed fish for welfare — with research supporting lower stocking densities, live feed enrichment, and slaughter improvements. Farmed trout are typically killed by percussion stunning or CO2 — methods that vary in humaneness.