Campeloma decisum reared in Minnesota Lake Superior water grew consistently well when clam meat or commercial fish food was provided and a substrate of sand or mud was present. Food alone, or the substrate alone, was generally ineffective in promoting growth. Thick substrates were more effective than thin substrates. Campeloma decisum tested in Missouri hard well water grew equally well with or without a substrate. A population of newborn snails from the St. Croix River, Wisconsin was reared throught three generations in 42 months on a diet of clam meat and trout chow with St. Croix River mud substrate. Survival of the original snails to 41 months was 80%.