"Red-sore" disease of fishes caused by the stalked ciliate Epistylis, is very common and widespread in the Southeastern U. S. Epizootics occur most frequently during the winter and spring months. Research has shown that this species is not an obligate parasite but only uses the host fish as an attachment site. The disc-like attachment organelle, penetrating the skin of the fish, apparently secretes an enzyme that dissolves the fishes' scales or spines and produces pit-like inflamed lesions. Bacterial infections often occur secondarily to the Epistylis infestation. Observations of the life history have shown a formation of telotrochs which are characteristic of the order Peritricha. Preliminary laboratory tests show that a single treatment with potassium permanganate at a rate of 2 ppm or formalin at a rate of 15 ppm will control Epistylis.