In my 10g I have 6 neon tetras, 2 platies, and 1 African dwarf frog. I am considering maybe two more neons, but that would be pushing the limit. They definitely need to be kept in schools, to reduce stress. I have read that cory cats are best kept in groups of 3 or more, too. Check out the species profiles link on the top of the page. If you want to learn about cycling your tank, just do a search on this forum, and a TON of results will come up. You will need to purchase testing supplies, at the very least for ammonia and nitrite, then at some point nitrate. Check out the articles link, too, as well as the archived help stickies, these areas have helped me out alot, and I still have a bunch of questions. Don't get discouraged, it is frustrating because of the information overload, but keep at it, and learn all you can.