Last year I fed FHM to RES in my aquarium for six straight months, my 5 RES would eat between 15 to 25 FHM a day. Every once in a while I would get a few sticklebacks mixed in from the bait shop and they never got eaten, not sure if my RES didn't like eating them or just couldn't catch them. I even had trouble catching the brook stickleback in my net. They are very good at getting in tight spaces and staying put. My best luck catching them was when I had the tank drained down for a water change. It's the reason I don't particularly care for them as forage.
