I agree with vwill. No new additions until you move all of those fish out into the pond. Goldfish grow very rapidly when they have room to move and grow. I have 2 Shubs that i got at about 1.5-2" about 4 months ago and both are right about 4" now. Also, with your current bio-load you should be doing almost daily water changes seeing as goldfish are very dirty fishies. I know you said you had high metal levels in your water, so I would suggest boiling a couple gallons at a time and putting them into a rubbermaid container or something like that to cool down over a few days and allow any other chemicals to evaporate out of the water, then use that for the w.c's. The other option would be to go out and buy like 6-7 one gallon containers of purified water (something like Deer Park or the store brand) at a time and leave it out to get to room temperature and use that to do your water changes. My guess is the boiling and rubbermaid would be your cheaper option.
