As a general rule, any game fish legally caught of legal size is the property of the person who caught it. All laws aside from length season liscence etc. apply to the regulation of commercial sale, and trapping/ netting. For instance we often use Bluegill for Catfish bait, it is legal as long as we catch the bluegill on a rod and reel. we can't buy them, and we can't net or trap them. It is still always a good idea to check with your local DNR before taking home a native fish. Now back to the subject, if you are looking for a pure wicked nasty fish, my vate goes to the bluegill, they are very similar to most cihlids, but downright nasty, they will beat up bass, sunfish and even channel cats of similar size, they are as dirty as any cichlid ever bred, so be prepared to do lots of maintenace. I have seen several of my friends wreck really nice tanks with the addition of a bluegill. I am not suggesting you try it but if you want a nasty dude, go catch a bluegill.
