For those aquatic animals whose lives are spent underwater, unique difficulties are encountered in treatment compared with their terrestrial counterparts. But for both, being raised in aquariums and other facilities means that original ideas are often needed for examinations and treatment to deal with their illnesses. At the Okinawa Churaumi Aquarium, a dolphin was successfully put under full body anesthetic, a first in Japan, and underwater ultrasonic imaging is also being used in diagnoses. This article introduces some of the initiatives being undertaken by veterinarians in the health management and treatment of aquatic animals.