I second the 'no goldfish' recommendation. Maybe with LMB but certainly not with perch. They quickly get too big for the perch to eat.

They are basically just carp and while not competing directly with the adult perch for food, they will grow very large and lock up a large portion of the biomass in your pond. I suspect they will compete directly with the very young perch but I'm far from an expert in such matters. Their offspring are numerous and predominantly brown.

My house came with a little pond and the pond came with goldfish. I managed to trap one that was 7" and I think there were bigger ones in there. Judging from the lack of little ones in summer of 2011 (when I bought the place), I think they were in there for two years at the most.

This past summer the pond (only .1 acres and 6' deep max) dried up. There were a few weeks where the water was down to 1' and about the size of a large car. I was still able to net dozens of the YOY goldfish. They are very tolerate of poor conditions.

Incidentally, the pond also went pretty low in 2011 (roughly 2' max depth). They were able to survive and fill the pond with YOY the next spring.

My opinion: if you put goldfish in, they'll get out of control quickly and you'll be fighting them forever.