I got 2 nice looking 3" oranda goldfish from my lfs a couple of weeks ago. They are the only 2 in the pond at the moment. However, I have 2 Ranchu's in a quarantine that will eventually move to the pond. I am not mixing my Ranchus with the orandas just yet because being that I got the orandas from a pet store, I have no history on them so they will be quarantined and treated with prazi and salt. My question is, when I switch them should I do a 100% water change on the pond? Will this harm my bio load?