Dolphin X, an approximately twenty-year-old intact male Dolphin residing in a closed aquatic ecosystem at a dolphin interaction facility in Mexico, presented to the veterinarians of said facility in February 2013 with a chief complaint of inappetance. The trainers initially noticed that Dolphin X had a decreased appetite. Within forty-eight hours, the patient’s clinical signs had progressed to moderate inappetance, aberrant behavior, regurgitation and expulsion of gas from the oral cavity. Dolphin X has a history of mild, infrequently-occurring gastritis, but this patient does not suffer from any chronic ailments and is considered to be a healthy adult. The physical examination revealed no new information, so the problem list was constructed from patient observation. This paper will discuss the: differential diagnoses for the patient’s problems, diagnostic tests utilized to determine the diagnosis of fungal gastritis in this patient, prognosis of fungal gastritis in dolphins, treatment chosen and clinical outcome for Dolphin X, as well as considerations regarding the practice of dolphin medicine in comparison to the practice of medicine in domestic species.