Some aquarium severum and oscar fish had been brought itSchool of Veterinary Medicine, Ferdowis Mashhad. In the head region and operculum of the fishes some holes have been observed. Physiological behaviour and feeding habitate of the fishes were normal. Poultry gizzard, cow heart and sheep spleen were incoporate in their diet. The lesions tested for presence of parasites were negative but, Aeromonas hydrophila has been isolated from the lesions. The fishes were allocated into two treatment groups, in the fnst group, oral oxytetracycline along with vit D was used and after two weeks signs of improvement was observed, the holes in the head region gradually shrunk and after one month the holes abolished. However, the fishes in second group which have been treated with oral oxytetracycline alone did not show any signs of improvement.
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