AbstractSwim bladders of juvenile rainbow trout Oncorhynchus mykiss were ruptured and subsequently observed for 28 d to identify healing patterns of swim bladder wounds and the effect of swim bladder rupture on direct mortality. Healing began within 7 d, wounds were completely closed after 14 d, and no mortality occurred. The healing process followed a pattern in which tissue first thickened around the opening (7‐14 d), scarring of the ruptured area occurred, and evidence of the wound ultimately disappeared (21‐28 d). The healing observed in juvenile rainbow trout suggests that swim bladder rupture does not result in direct mortality as was hypothesized; however, the indirect effects of swim bladder injury (e.g., a decreased ability to swim efficiently) may lead to mortality by predation or other natural phenomena that were not observable in this study.