Zebrafish have become the second most used vertebrate in research, yet their welfare needs are often poorly understood and inconsistently addressed in laboratory settings.
Zebrafish welfare has been systematically neglected compared to mammalian research animals, partly because their small size and aquatic nature make welfare assessment less intuitive. Yet the scientific evidence is clear: zebrafish have the neural architecture and behavioral responses consistent with pain and stress experience. Millions of zebrafish are used annually in research conducted under welfare standards far below those applied to mice or rats. Improving zebrafish housing to meet social needs, refining procedures known to cause pain, and developing species-appropriate welfare assessment tools are urgent priorities.