Thank you so much, that was extremely helpful. :) I did try looking around for some sort of guide before asking but there are so many different versions it is pretty overwhelming. If I enjoy this little guy I might consider a more advanced one in the future.
I just bought one of these doodads at Walmart, I think it said gen 3, 20th anniversary edition. So far all I have seen are two icon options, a food ball and some kind of crisscross food thing. Are there no health bars or anything? I don't know how to tell if it is hungry or happy.