Stocking a 10 gallon?

I have a 10 gallon tank cycled and ready for creatures. I am looking for some CREATIVE suggestions of things to add. Can be fish/crustaceans/both brackish or fresh water. Things that will get along and live their entire life in a 10 gallon. The tank is very full of rocks and caves stacked in layers. (I would estimate the rocks take up at least 2-3 gallons of water volume). Please only reply if you are going to put a little more effort in to this besides "you should get a betta".