Cycled my last tank with a bunch of common harlequin rasboras. Put them back in their regular tank when I was finished. I like them a little too much to use them as food because they school very tightly and are cooler to watch than most little fish.
I never heard of it. Guess it could work, maybe possibly? I use goldfish. I just haven't taken them out to put anything else in yet. They kinda grew on me. lol