Hi, I have a 55 gal tank with 4 African Clawed Frogs, 2 Spotted Pimelodus, 2 Sailfin Plecos, and a bunch of Goldfish num nums for the frogs. The Frogs seem to be having a problem catching the Goldfish. I usually buy 4 dozen at a time, and when I first put the Goldfish in the tank the Frogs can...