Hey! Check this out! I will on one month feed my oscars feeder goldfish (from the pet store) and then the next, minnows from a local hardware store! In the summer/spring months, I go down to the Milwaukee river and catch as many crayfish as I can and feed those to them!! I have a holding tank that I put of all my live bait-fish in for at least two weeks as I also add some anti-parasite meds. as well. Upon one purchase from the hardware store, I bought about six dozen minnows and put them into the holding tank. A couple of weeks later as I was retrieving dinner for my cute couple, I noticed a rather weird looking minnow! Turns out that it was a Canadian "Stickleback"!! I tried to keep it alive in my guppy tank, but it died a few weeks after that! In-fact, I've gotten a few unusual "stow-aways" when I purchase feeder fish including my bullhead catfish, "Buddy"! I still say there's nuttin' like watching my Ollie and Olivia chow down on a good sized crayfish!! It must be like us eating lobster!!
