After thinking about it, if they didnt come from the fish farm the only way a fish could have gotten in is my overflow. I have a 4" pipe running to a ditch about 40 feet away and for about 2 days after the pond filled up I didnt have a screeen on it. I wouldnt have thought they would have swam against the current in the overflow while it was draining and after it was finished draining there was no water in the pipe. I know fish can appear in ponds over time but mud cats that size in 1 year? There are plenty of other ponds around and we get ducks and other birds all the time. Is it a possibility that those mud cats came as eggs on birds and are that big already? I would find that hard to believe without expert opinions. I would tend to think they came as small fish. Is there any logical way they came naturally and not from the farm. We started digging the pond on Mar 2 of last year and it was about half full by the end of that month.