In the winter of 2015, a skin ulcer disease outbreak occurred in a pharaoh cuttlefish Sepia pharaonis population cultured on a land-based fish farm in China. Affected cuttlefish (about 60% of the population) were characterized as having developed ulcers on the dorsal skin, fin fringe, or distal mantle tip. Masses of a ciliated protozoan were isolated from skin ulcers. The ciliate was identified...