In a message dated 5/17/02 3:54:35 AM Eastern Daylight Time, Aquatic-Plants-Owner at actwin_com writes: << I just wish I knew what these things are! TIA, Steff landlocked in New Hampshire >> They are freshwater limpets, quite common in some areas and they can get up to about 5mm. As far as I can tell they are harmless to plants. Moon