My little 3 gallon open-topped red cherry shrimp tank at work has never had a single shrimp 'escape' (knock on wood). The snails, on the other hand, sometimes crawl out and keep on going until they forget where the water is, I guess (scratching head). Betty Goetz _______________________________________________ GSAS-Member mailing list GSAS-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/gsas-member