Removal and identification of the neoplasm from the corner of the mouth of a marbled sailfin pleco (Pterygoplichthys joselimaianus WEBER, 1991) - Case Study

SUMMARY Background: The authors examined a marbled sailfin pleco (Pterygoplichthys joselimaianus WEBER, 1991) brought to the clinic of the Department of Exotic Animal and Wildlife Medicine of the University of Veterinary Medicine in September 2016. The owner purchased the animal in January 2016 in a special aquaristic shop. The owner kept the fish in a 350 l tropical aquarium with other small sized fish species (Paracheirodon innesi, Danio margaritatus). Objectives: During the physical examination there was a lentil-sized papilloma-like tumour in the right corner of the mouth. Due to the increasing growth rate of the tumour the veterinary team of the clinic decided to perform removal surgery on the fish. The authors used the removed tissue to perform histopathological examination to identify the type of the tumour . Materials and Methods: The veterinary team examined the fish and prepared the anaesthesia bath. The bath contained 0,170 mg/ml MS-222 (tricaine meth anesulfonate), an anaesthetic commonly used in fish veterinary procedures. After removing the tumour, the wound was treated with Betadine ointment. The tissue was fixed for 24 hours in buffered formalin. After the fixation the sample was infiltrated and embedded into paraffin blocks. Leica manual microtome was used for section cutting. The prepared histological slides were stained with haematoxylin and eosin and were examined with Olympus CX21 microscope. The identified tumour was compared to neoplasms found in other ornamental fish species described earlier in literature review. Results and Discussion: After the results of the histopathological examination the tumour was identified as a papilloma. According to the authors’ hypothesis the tumour was caused by a mechanical trauma or an injury. Nowadays in aquaristic owning high-priced fish species is increasing in popularity. However, these valuable species require adequate veterinary supervision, prevention, diagnostics and treatment as well