Roughly where in Florida are you? That is going to make a big difference. No matter what you have lots of options for "other" fish. Not all are monsters. I saw a guy in Naples that had a Mbuna and goldfish pool conversion that was amazing. If you are up near Jacksonville your options are different. Sturgeon are definitely going to be difficult in the summers. High fin banded sharks are a great call. I had one in pond for a few years until an otter moved in.
I have wanted to do phoenix barbs. Depending on where you are in Florida I have seen people do black labeos in ponds. Some people do channel cats and iridescent sharks with koi but you need large koi. I have seen Pacu do well in ponds in central Florida. While not monster I have heard roseline sharks do well in ponds in Florida and they look great in large schools of 6 inch fish. Leptobotia elongata is supposed to be cold tolerant enough, but I haven't seen it done. Large schools of rosy barbs are cool in there as well. Again if everything is well fed Florida gar would be fine. Bala sharks and tinfoil barbs are usually done in uncovered ponds in Florida. Gold barbs do well outside. Buenos Aires tetras do really well in ponds in Florida. All of those look great in schools. I think most of the dawkinsia barbs will do well but I haven't tried. Don't laugh but gold Chinese algae eaters will do fine. If you haven't seen them at 6-7" you are missing out. Blackfin goodieds get big (for a goodied) and have been done in ponds. Gouramis do well in ponds three spot and snakeskins will be easy. Pink kissers and giants will depend on where you are. Hoplo catfish do well also.
Don't rule out natives either. Golden shiners get nice size and look good. If you can get young finger mullet acclimated to freshwater they would be interesting in a pond and they grow pretty big. I hate to even offer it as it really depends on where you are, but our native freshwater ray could be an option. They used to be collected out of Lake George. They do better with a little salt, but can be full fresh if your water is very hard.
In a full size swimming pool you could do some cichlids in there and they will stake out a territory without hurting the koi. I wouldn't do dovii or festae, but mayans and gymnogeos would work. Again depending on where you are viejas or fire mouths might work.
In extreme south Florida you might get away with archerfish.
thebiggerthebetter
