I agree with freemike. But, it's all personal preference. I, myself, am not a huge fan of pond snails. While they are totally harmless, they do like to multiply...not an outragerous number. But, still...

I guess I am the odd one out here. I spent my whole day taking down my 10 gal tank and removing the pond snails...and rehoming them to my aunt who doesn't mind them in her tank. I would also go with an assasin snail--wish I'd thought of that before I took down entire tank. Had one full grown one, an 5 itty-bitty babies snails. Guess I didn't quarantine my plants long enough. But if you want to keep them in a Kritter keeper, don't see why that wouldn't work. ;)