Sure you can. But how long will it take versus hiring a dozer to do it in a few days? And what will you do when you've got it dug a few feet deep and then it rains. Now you've got a mudhole until it dries out again. And then you get to go bog around in it trying to dig some more before it rains again.
I hired a dozer to dig mine. A few days later I had an approx one acre pond that was about 14 feet deep. A couple of weeks later it came a 7.5" rain and filled it completely up, and in fact overflowed around the backside of the dam. (7.5" in 12 hours will do that.) I stocked it with catfish, bluegill, perch and minnows, and I go feed them every couple of days.
If I had tried to dig it with my tractor, I'd STILL be out there bogging around. And I'd have a partially dug mudhole to deal with.