when I can find home-bred fish, I will buy from the breeder, but I haven't seen consistently healthy fish from a fish store. My 2 male guppies I bought to refresh the color in my colony are doing well, my corydoras catfish, both bronze and trilineatus, are doing well. I might eventually consider quarantining some more bronze to enlarge that group, I only have 4, and I think all are the same sex. Trilineatus I am thrilled with, healthy and breeding now (after an antibiotic run last year which they needed), I want to move them up to a larger tank soon. German blue rams were healthy, although I'm down to a single male, I simply can't do daily water changes for perfect conditions for them. But tetras - only healthy ones I have found came from an individual, and I won't buy more at a store, nor platies, mollies - I could add salt to my tanks and buffer them, but I'm not bothering.