Hi. We have some goldfish and small koi (as well as some larger koi and goldfish (6+ inches)) in our outdoor pond. I am not worried about the large comet goldfish or koi, but there are several smaller goldfish (5 orandas and ryukins I think), 2 or 3 baby koi, and a small koi with scoliosis. The pond is 1,500 gallons with a waterfall, about 2 and a half feet deep and we are getting a de icer, but I know it will get very very cold. I have a 55 gallon tank we can keep them in indoors. I am in central Virginia. The temps are about to drop into the 30s at night and I want to get them moved in if I need to before the temps drop.