Only tropicals, no koi or goldfish. There are Mollies, Guppies, a couple Plecos and 9 Angel Fish. I've heard that cold water fish don't do as well here in the tropics, that they are subject to more disease. There are koi here for sure, in all the fish stores and I've seen some large ones in private and public ponds. I just decided to stick with the tropicals. The outside pond is mainly a water garden and I wanted lots of small schooling and colorful fish to keep the mosquitoes down. I have that, there's at least a thousand small fish in there. I'm giving them away when I can and I've increased the number of Angel fish as they are predators and eat the fry of the smaller fish. I also didn't want to attract any other predators, birds, possums or coatamundi. I have 3 big dogs and 10' rock walls but the dogs sleep sometimes and I just didn't want to get attached to large fish and then lose them. The inside pond is where I want larger fish. I thought about koi for that one but decided to get medium sized cichlids instead, I have about 10 small ones in there now, Convicts, Lemons, Firemouth, Jack Dempsey and I'm not sure of the names of the others. They are only a few inches long now but should get to about 6" eventually.
Here's one of the Plecos cleaning a rock today.
and one of the flame guppies to the right of the lily in this pic, the others are Marble Mollies and Pearl Sailfin Mollies.