On Sat, 10 Jul 2004 17:38:14 +0200, "Jürgen Beisser"
wrote:

This Physa sp. seem to be very effective remover of algae, as it is written
in http://www.diewasserwelt.de/blasenschnecke.htm. It is a German page, but
even if you can not understand the text, look at the pictures. I never heard
that these type of snails does harm to any plants.

Thanks that is the snail I have and getting a rough translation it was
clear that they are prized for getting rid of algae. So am definitely
going keep them and let them get on with keeping algae at bay.