I wouldn't. Trash could build up on the fence and keep the spillway from doing it's job. Instead of fish, you could lose the dam.

Most fish go upstream in rising water. Some small fish will probably be sucked over the dam but the loss will be small.

6 ft seems a little small to me for 1.5 acres with a lot of runoff.

It's not about the fish. It's about the pond. Take care of the pond and the fish will be fine. PB subscriber since before it was in color.

Without a sense of urgency, Nothing ever gets done.

Boy, if I say "sic em", you'd better look for something to bite. Sam Shelley Rancher and Farmer Muleshoe Texas 1892-1985 RIP Grandpa