Protein compounds were extracted from the mucus of sea anemone, Stichodactyla haddoni, and their effects on the gills of rainbow trout, Oncorhynchus mykisswere examined. Sea anemone samples were collected from the intertidal zone of the eastern coast of Hormuz Islandand frozen samples were transported to the laboratory. Then the mucus was extracted using of the PBS solvent and doses of 5, 10 and 24 mg/dry weight of total protein was injected into the tail vein of the fish. Upon the inactivation of fish, histopathological changes were examined using of the classical histological method. Lethal signs were observed in the gills, including aneurysm, hypertrophy of epithelial cells, lamella clubbing and deformation, subepithelial edema, lamella congestion in the interlamellar region and necrosis. The damages were more serious with increasing doses. The results showed that protein compositions of the mucus can cause numerous lesions in the gill tissue of fish, which act as an excretory, respiratory and ionic regulation tissue, the failure of which can lead to failure of fish’s vital functions that can be one of the reasons for the death of the hunted fish.
The results showed that the protein compositions of mucus can cause numerous lesions in the gill tissue, as an excretory, respiratory and ionic regulation tissue lead to failure of it functions that itself can be one of the reasons hunted fish death.