Immersion anesthesia with alfaxalone in a goldfish (Carassius auratus)

An alfaxalone anesthesia protocol was used to perform a coeliotomy in a goldfish diagnosed with multiple ovarian cysts. The 7-year-old, 460 g, female goldfish presented for severe coelomic distension and anorexia. Full-body radiographic images were unremarkable, but coelomic ultrasound revealed multiple ovarian cysts. Ultrasound-guided aspiration of a large cyst was performed. Cytology revealed lysed leukocytes that contained numerous intracellular bacilli suggestive of septic suppurative inflammation. An exploratory coeliotomy was performed and 90 mL of semi-clear fluid was aspirated from the largest cysts. For anesthesia, three plastic fish tanks were prepared for induction (10 mg/L of alfaxalone), maintenance (5 mg/L alfaxalone), and recovery (no anesthetic agent). Water in the fish tanks was saturated with oxygen. The goldfish was immersed in the induction tank and once the labyrinthine-righting reflex was lost (5 minutes), the fish was placed in the maintenance tank. The goldfish was then placed on a platform and supported in a supine position on wet Perlon wool. The head of the goldfish was submerged in water while the coelomic area of the surgical field was maintained out of water. During surgery, the respiratory rate (32 to 53 opercula movements per minute) and heart rate (35 to 45 beats per minute) were monitored. Butorphanol (0.4 mg/kg IM) was administered for analgesia. The anesthetic event was 60 minutes, with the recovery period being 35 minutes. There were no complications associated with recovery and the goldfish returned to its normal position 12 hours after surgery. Immersion anesthesia with alfaxalone permitted deep anesthesia for surgery with an uncomplicated recovery. The anesthetic protocol described appears to be a safe and easy protocol for general practitioners and, furthermore, uses anesthetic agent commonly available to veterinarians.