The flower horn fish (hybrid cichlid) was first produced in Malaysia and is believed to be the result of hybridization between the Midas Cichlid (Amphilophus citrinellus) and the Threespot Cichlid (Cichlasoma trimaculatum). This fish is also believed to have emerged through selective cross-breeding of the Threespot Cichlid (C. trimaculatum), Guayas Cichlid Cichlasoma festae, and Jingang blood parrot cichlid (another hybrid) in 1996. The flowerhorn fish and the Threespot Cichlid are becoming increasingly popular as a pet, especially in Southeast Asia.
Materials & Methods:
In September 2014 and August 2015, a three spot cichlid (Cichlasoma trimaculatum Günther, 1867), a long bodied and a short bodied flower horn fish (hybrid cichlid) were referred to the Faculty of Veterinary Medicine with progressive anorexia, abdominal distention and increased respiratory rate. No parasite or ova was observed in wet smears of skin, gills and faeces of all fishes. The fishes were anesthetized in 100 ppm PI222 (Pars Imen Daru, Iran) (PI222 is an herbal medicine and contains “eugenol, carvacrol, eugenol acetate and some other effective substances” as the active ingredients). Standard digital radiographs were taken in right lateral and dorsoventral (DV) projections.
Results & Discussion:
Right lateral radiographs showed increase in size of soft tissue mass in ventral abdomen and decrease in size of swim bladder. Ultrasonography was performed from the left side of all fish. Ultrasonography of visceral organs showed free fluid and an enlarged liver, containing multiple cysts of various sizes in all cases. At necropsy, free fluid in the abdominal cavity and several cysts in an enlarged and pale liver were observed. Cysts were delineated by a thin layer and filled with clear fluid. No internal parasites were observed in 3 cases. Also no bacterial growth was observed after 72h. Histologically, The cysts walls were composed of squamous epithelium and some contained eosinophilic and proteinous fluid. Numerous sinusoids were dilated by red blood cells. Severe fatty changes were seen in hepatocytes. Histological lesions in the gills were hyperplasia of lamellar epithelium, fusion of lamellae and mild proliferative bronchitis. On the basis of the macroscopic and microscopic characteristics, origin of cysts and cause of this condition remained unknown. However, genetic predisposition appears to be the best explanation for these lesions.