lol.. I don't think its the right time of year to attempt to add any kinds of fish to it. Chances are you'll never be able to do goldfish either. If you could get some koi 16"+ koi they might make it with the other fish in the pond. My girlfriend has a pond thats about a acre. Her parents get pissed when I fish there because they are their "pets" but the pond is a natural one and its ridiculously overstocked. I would imagine if the world was without people all ponds would be as full as this one. You can stomp on her deck and every fish in the pond literally swims to it waiting for you to throw them handfulls of food. There 6 2'+ koi in there, small mouth bass, large mouth, sun fish, blue gill, big cats (don't know the species, but they average about 20" each and the bigger ones are about 32") and maybe perch. I really need to catch some pike and muskee to throw in there to even out the population. I told her parents I had some 10" piranha I no longer had room for and her pond sounded like a easy place to dump them (obviously joking) and they both flipped. Anyways.. Give it time and try getting a pond heater if you don't want it to freeze over. You can get them for like $20 at petsmart this time of year on clearance, I thought about using one in my 130gallon lol. Its obviously not going to keep a lake from freezing but it should keep about 10feet of ice melted in each direction of the heater. Either that or put a huge pond aerator, thats what my girlfriend has and her pond didn't freeze all winter. Hers is also spring fed too so it doesn't freeze that well.