Matthew writes: > Where do you live? If your anywhere near the Great Lakes they could very > well be specimens of the dreaded Zebra mussel. Zebra mussels are not mobile. They glue themselves in place like a barnacle. I'll agree with the limpet ID. The shell shape and pattern can be used to identify which one. Bob Dixon Cichlid Trader List Administrator http://cichlidtrader.listbot.com