You are likely thinking of the rockfish/scorpionfish/lionfish/frogfish group. They are all carnivores. If you are truly thinking of a stonefish (Synanceia sp.), they grow large, as Bev said, and are extremely poisonous. If you were gutsy enough to attempt one, you would need a very large tank and it would be the only fish you would keep. Coupled with that it would be a ravenous eater and require high-end filtering devices. Some frogfishes stay small and would work in a nano, with the proper diet. Find out what species you have access to and then research, research, research. Personally I would be waiting until I had spent more time in the hobby before attempting one of these fish. Do not rush into buying one just because they are available.
Coral banded shrimps are an ideal candidate for a nano, once again, be sure to do your research.
Search the forums here, as well as on Reefcentral, and perhaps check WetWebMedia to get a basic idea of whether the fish or the shrimp will work for you.
http://www.wetwebmedia.com/marine/fishes/index.htm