I too agree with BG, RES, and LMB. But some harvesting should be done annually. Definitely do not put catfish in if you are not going to be able to maintain the pond. They will probably not reproduce, but they will become monsters that become the top predators. And when they get big, they are darn hard to catch.
At some point, if you begin to see weeds appearing, it may be worthwhile putting in a couple of grass carp.
