COLDWATER DISEASE
a bacterial disease of juvenile and yolk-sac fry of salmonids caused by Cytophaga psychrophila (or Flexibacter psychrophilus). It occurs at temperatures below 10°C and is an external and systemic disease with lesions on the fins skin and muscles, often concentrated on the caudal peduncle. Survivors may lose the caudal fin. Severe outbreaks leave fish lethargic and spinal deformities develop, or some fish may show spiral swimming, dorsal swelling and dark pigmentation on one side of the body; mortality is common. Also called peduncle disease or low temperature disease