Ok I want a group of cory's in my tank and wanted to get input on the different kinds my LFS has. There are 3 different kinds, panda cory's, paleatus cory's(I think these are the peppered ones), and long fin cory's. Any reasons I should pick one instead of the other? Also how many would I need I think I've read 5 or 6. And what and how much do I feed them?