I use a 4 bin rotation to quarantine bait minnows. I don't use feeder goldfish because the copper levels in them will kill my AST, albino RES, brackish/marine predators, and the large inverts I maintain. And, they can cause liver damage to my FW predators, as well. With fish like my albino aethiopicus, pair of AULs, 7 mbu puffers, 15 dragon puffers, leichardti aro, Siniperca, 30 polys, 6 Af & SA lungfish, plus a few thousand other fish... why risk their health?
I breed LBs to have food available for young fish. But, I'd need a couple of large ponds to be able to supply the couple of thousand live fish I feed out every week.