Family Bithyniidae Bithynia leachii(Sheppard,1823) The shell is 12mm high and 7mm wide,it is cone shaped and can be lightbrown or yellow-green. The body is grey with yellow dots,tentacles long and slim.The eggs are usually laid around May and hatch after 3 weeks.After 6 months the snails reach maturity. They live for up to 3 years. The snails feed on bacteria,rotting plants in quiet,sweet water. In North-Africa to East-Europe.Bithynia tentaculata(Linnaeus,1758) The shell is 9-15 mm high and 6-9 mm wide.It is ovoid conical and has 5-5,5 whorls. The body is dark-brown with yellow spots,tentacles are shorter than those of B.leachii.Eggs are laid in May-August and hatch after 2-4 weeks. They feed on debris in the mud,in quiet or streaming sweet or saltish water. It is most common on stones at the banks of rivers and canals. In Northwest Africa,Europe to western Siberia,imported in North-America.