I have had great luck with nano sized tanks. Just always remember that when things start going wrong in small volume tanks that it gets bad quick. Watch your parameters (Water Quality). As far as fish, I have a Clownfish in a small tank. You just can't get crazy and overstock. In a 10 gallon I would have a Clownfish, shrimp and then easy corals like zoos, rics and the such. You will be suprised how nice these tanks look when you take the time and research things. You are off to a very good start by checking on this forum. Good Luck