Abstract

An adult female electric eel (Electrophorus electricus) presented to the attending veterinarian for evaluation of a progressive skin lesion that had not responded to empirical antibiotic therapy. The patient, a two-year resident of an isolated exhibit within a large aquarium facility, was anesthetized with MS-222 buffered with sodium bicarbonate to permit examination. During examination, ventilation was provided via bilateral water flow over gills, as well as spontaneous oxygen breaths every five minutes. Diagnostics and sample collection included radiographs, ultrasound, skin scrape for cytology, punch biopsy for histology and culture, and venipuncture via the caudal tail vein. The radiographs, ultrasound and skin scrape were unremarkable. During one venipuncture attempt, positive pressure was noted and the needle was promptly removed. The eel made a quick and uneventful recovery; however, upon return to its exhibit, air bubbles were visualized exiting the venipuncture site and the eel acutely arrested. Postmortem radiographs and CT revealed perivascular gas around the venipuncture site. At necropsy, a hematoma was noted within the swim bladder at the level of venipuncture, while internal organs were grossly normal. Microscopically, multiple clear spaces, often with round margins consistent with air emboli, were present within the ventricular myocardium and in adventitial tissues adjacent to the venipuncture site. To the authors’ knowledge, this is the first report of an air embolism documented in an electric eel and raises the importance of knowledge regarding the intricate anatomy of the electric eel and risks associated with venipuncture in this species.

Acknowledgements

The authors wish to thank the Georgia Aquarium veterinary and husbandry staff for their commitment to excellence in animal care as well as the radiology department of Blue Pearl Sandy Springs for their assistance in the advanced imaging of this specimen.

* Presenting author