A Post-Operative Follow-Up of an Endangered Saltwater Fish Lensectomy for Cataract Management in a Public Aquarium: A Case Series

SIMPLE SUMMARY: Ocular pathologies, such as cataracts, may affect fish welfare. In severe cataract cases, complications such as anorexia, low body condition score, skin wounds, and scoliosis from chronic abnormal posture may develop in fish. Ultimately, cataracts may be associated with an inability to feed, cachexia, and death. The major surgical treatment of cataracts in fish is lens extraction. Although several cases have been published, little is known regarding the outcome and long-term prognosis of fish undergoing lens extraction. Eleven fish housed in a public aquarium had their lenses extracted after mature cataracts were diagnosed. As lens extraction was bilateral in four cases, follow-ups were available for 15 eyes. Following lens extraction, 73% of the fish resumed feeding, regained a normal body condition score, and appeared clinically normal. Surgical technique and post-operative complications are further detailed in this article. This study reviews the clinical outcome of lens extraction and could help clinicians improve the management of cataracts in fish. ABSTRACT: Mature cataracts can be a life-threatening condition in fish as it may result in anorexia. Lens extraction has been previously described in fish, but the long-term outcome of this procedure has not been evaluated. Eleven captive-bred adult fish housed in a public aquarium presented with unilateral (n = 3/11) or bilateral (n = 8/11) mature cataracts. All cases belonged to three endangered fish populations: striped bass (Morone saxatilis) originating from the Saint Lawrence River and Atlantic and spotted wolffish (Anarhichas lupus and Anarhichas minor). Pre-operatively, fish presented with anorexia, dark discoloration, abnormal position in the water column, skin abrasions, and/or decreased body condition scores. A lensectomy was performed in eleven fish, including a bilateral procedure in four fish, corresponding to fifteen eyes. Follow-up examinations were performed one to two weeks and one year post surgery. The main complication was self-resolving: corneal edema was present in 67% of eyes, persistent after a week in 47% of eyes, and resolved thereafter. Post-operatively, 73% of fish resumed feeding and regained a good body condition score. Persistent visual impairment post-surgery associated with anorexia required euthanasia in three out of eleven cases. The median time of death was 336 days post surgery (range: 27–1439 days) and three cases were still alive 1334 to 1425 days after the lensectomy. This was considered a favorable outcome for these older individuals with concurrent diseases.