Enteric redmouth disease

Enteric redmouth disease, or simply redmouth disease is a bacterial infection of freshwater and marine fish caused by the pathogen Yersinia ruckeri. It is primarily found in rainbow trout (Oncorhynchus mykiss) however, and is characterized by subcutaneous hemorrhaging of the mouth, fins, and eyes. Hemorrhaging also occurs on internal organs, and in the later stages of the disease the intestines become filled with a yellow fluid. Redmouth disease was first discovered in Idaho rainbow trout in the 1950's.[1]
Some fish species serve as vectors for the disease and have subsequently spread the pathogen to other parts of the world.[1] An example is the fathead minnow (Pimephales promelas) which is responsible for the spread of redmouth disease to trout in Europe.[2] Other vectors include the goldfish (Carassius auratus), Atlantic and Pacific salmon (Salmo salar), the emerald shiner (Notropis atherinoides), and farmed whitefish (Coregonus spp.). Infections have also occurred in farmed turbot (Scophthalmus maximus), seabass (Dicentrarchus labrax), and seabream (Sparus auratus).[1]
There are several antibiotics available for the treatment of redmouth disease in fish. The disease does not affect humans.[1]

http://en.wikipedia.org/wiki/Enteric_redmouth_disease