I'm pretty sure this doesn't go here, but I wasn't sure where else to ask. A few weeks ago, I noticed these oldy colored common snails. Or what I thought was a common snail. Upon closer inspection, I found that their shells are jet black, with gold polka dots. I have searched the internet and found no mention of these old snails.
Has anyone else seen them, or do you have them?

Oh and I found an Albino common snail in my tank this afternoon, when I did my daily tank inspection (seach for my newly introduced RCS, check on my plants, ect.). Could there be something wrong with my water? Or are these new inhabitants normal?