This isn't really advice but I was in [store] and there was a HUGE roach floating in a tank with some goldies and disjoin loaches. It was still alive and I told the "expert" fish guy and he said that the goldies eat them.
not advice either but i was at my local county fair today and they had about 50 hermit crabs in a 10 g 100 goldfish in a 20 and a bunch of glofish in a half filled 5 gallon fluval spec with white trim!!!! i cant believe they had glofish. goldfish were if you made one ping pong ball in the cup, hermits were if you made 3 and glofish were if you made 5 out of 5 throws