IMO, you have a nice size tank, you should put whatever fish you enjoy the most, "no one" in this world can gurantee you that any fish is peaceful or aggressive, everyfish has its own personallity, I'm sure everyone here seen nasty clownfish, or peaceful triggers. Is difficult to determine which is what. By removing a fish from the ocean and judge what size tank this fish should be in is unrealistic also, and to determine if it will grow to its potential size, once you tank a fish out from the ocean it'll NEVER reach its potential size. If you just spend a little more time on your tank/tanks daily, anything can be done, luck is another factor.