Cochliopodium minus, a scale-bearing amoeba isolated from organs of perch Perca fluviatilis

A scale-bearing amoeba isolated from gills and other organs of perch Perca fluviatilis Linnaeus, 1758 was identified as Cochliopodium minus Page, 1976. This assignment was suggested by light microscopy and confirmed by ultrastructural study of both the strain isolated from perch and the environmental strain of C. minus (CCAP 1537/1A) serving as a control. This has been the first electron-microscopic definition of C. minus and, in addition, the first identification of an amoeba with a theca-like cover found to infect fish. The ability of the fish strain of C. minus to colonize gills and also internal body organs was proved experimentally.