Zebrafish have become one of the most important laboratory model organisms, and research confirming their pain capacity has significant implications for how they are used and housed.
Zebrafish research welfare represents a case where scientific progress - demonstrating the capacity for pain - has outpaced regulatory frameworks governing the species' use. The vast numbers of zebrafish used in research, combined with evidence of their pain capacity, creates a welfare situation of considerable scale. Laboratory housing for zebrafish typically prioritizes space efficiency over behavioral welfare, with small tanks providing minimal environmental complexity for animals that show complex social behavior and environmental exploration in naturalistic settings. The regulatory exemption of larval zebrafish from welfare protections in many jurisdictions is increasingly questionable as evidence of nociception at early developmental stages accumulates.