Well, they are definitely the "bad" snails. I only have the one pond snail though. He is the one I really like. I will move him to the 5.5 with my betta. the others I believe are ramshorn. They aren't as circled like that in the center yet but maybe they have to be larger. They are patterned and colored like that though exactly. I may take one of the larger ones of them and thrown in the 5.5 for now as well. They are both fairly small at the moment. Would like to know what they look like when they are bigger. Here is the site I found them at.
http://www.otocinclus.com/articles/snails.html