That is a big factor, Phole....when I got the pond, I didn't drain it or kill off the existing fish....it was already stocked with a few channel cat and bream, so I added 500 white crappie and 500 black crappie to get them established....they were about 5 inches long, when I put them in....that worked well, so the next year, I then added 200 Florida bass....the next year I added 100 spotted gar....I didn't want those big ole gator gars, so I opted for spotted gar, which only get up to about 10 pounds.
Oh yeah, almost forgot, I also added 25 grass carp about 12 pounds each, to help with the vegetation.
I can always adjust my program, but for now, I'm tickled pink !!!