I purchased some silver dollars from a new LFS the other day that were a little odd. They have dark spots over their body, with a red tinge behind the gill plate and some red on their bellies. The guy at the LFS tried to tell me they were a hybrid of piranha/SD. I don't really care, b/c I was simply after silver dollars. They are about 2"-3" at the moment. I just want to know, could he be right?