Histopathological Effects of Formaldehyde (CH2O) on Rainbow Trout (Oncorhynchus mykiss Walbaum, 1792)

Formaldehyde is commonly used as a disinfectant and also in a control of fish disease in aquaculture sector. However, this widespread use, can lead to environmental degradation and can cause negative effects on the treated fish with. In this study 250 mg/L (1 hour) and 500 mg/L (45 min) concentrations of formaldehyde were used. From the results of the histopathological findings degeneration was determined in the epithelial cells and pilar in the gill lamellae, lymphoid infiltration interlamellar necrosis and degeneration of the muscle tissue, dilatation in the liver, congestion in veins, degeneration in hepatocytes, damage in the blood vessels of fish which were treated with formaldehyde. In conclusion; formaldehyde was found to have a negative impact in histological examination in applied rainbow trout. Therefore, it was concluded that it should be used consciously and according the needs in aquaculture.