I have a 1000 gallon pond that normally has two air pumps and a waterfall going. In the east coast blizzard recently, a power outage caused my pond to totally freeze over for about 16 days. The pond is quite unfrozen now, but the 15 3" goldfish have not appeared. Was a 16 day total freeze over enough to kill the fish? [There are plenty of places for them to hide, but just worried]