Potential for recovery in nodular gill disease of rainbow trout, Salmo gairdneri Richardson

Abstract. Nodular gill disease characterized by severe multifocal epithelial hyperplasia was diagnosed in a group of rainbow trout, Salmo gairdneri Richardson, fingerlings. Gills of a large proportion of fish transferred from the affected tank to smaller aquaria showed a marked decrease in severity of the lesions after 2 months. Repair of hyperplastic lesions may occur in various forms of proliferative gill disease, provided that the basement membrane lining the primary and secondary disease, provided that the basement membrane lining the filaments and lamellae remains intact.