Under pressure: Use of hyperbaric chamber therapy for management of dissolved gas disorders in fish—15 cases (2015–2025)

OBJECTIVE: Our objective was to describe clinical findings, treatment protocols, and outcomes in captive fish presenting with ocular and/or buoyancy disorders attributed to dissolved gas disease undergoing novel treatment with hyperbaric therapy. METHODS: Electronic medical records were reviewed for 15 teleost fish comprising 10 species housed at a public aquarium and treated between 2015 and 2025 with hyperbaric chamber therapy for exophthalmos (n = 8), intraocular gas (n = 5), buphthalmos (n = 5), and/or positive buoyancy (n = 7). The collected data included diagnostics, adjunctive therapies, hyperbaric chamber course and parameters, response to treatment, recurrence, and postmortem findings when available. RESULTS: Initial clinical improvement in response to hyperbaric therapy was documented in 10 (67%) of the 15 fish, with long-term resolution (1 month: n = 1; 5 months: n = 1; >18 months: n = 5) of clinical signs observed in 7 (47%) of the 15 fish. Three fish (21%) died during chamber treatment. Necropsy and histopathology identified infectious comorbidities in multiple nonresponders (n = 6). CONCLUSIONS: Hyperbaric chamber therapy was associated with meaningful short-term (instantaneous to <12 h) clinical improvement in many fish, particularly those with ocular presentations. Recurrence and mortality were common, most often in cases with severe and/or comorbid disease. Hyperbaric therapy may be a viable modality for the treatment of dissolved gas disorders and warrants further investigation.