Abstract: Histopathological and clinic observations of skin ulcers disease was conducted by conventional paraffin section preparation method in koi carp Cyprinus carpio koi cultured in ponds（No.1 and No.2）from Shanghai Chaoyang koi carp farms.The results showed that the typical lesions in ulcers were found including a large number of congestion，inflammatory cell infiltration，inflammation，degeneration and necrosis in muscle bundles.These pathological features were caused by local infection of the ulcer bacteria，without infection on the whole body. There were highly consistent pathological changes including vasodilation，blood wall thickening，peripheral parenchymal tissue，coagulation and degeneration in all samples.Some red blood cell necrosis was found in yellow bubble-shaped and degeneration area and coagulation necrosis deterioration was observed in splenic tissue，indicating that obvious lesions of spleen were caused by toxic substances in the blood，hematopoiesis and blood storage capabilities.Pathological changes were found to be less in hepatopancreas and kidney than those in the spleen，with normal intestines，heart，gills，head-kidney and other tissues.In summary，spleen solidification degeneration，hepatopancreas tissue congestion，congestion and renal interstitial tissue vasodilatation，and blood wall thickening were the same pathological changes in all samples，which were not involved in skin ulcer disease.
2016, Vol. 31 
