I have mostly juvenile scud now in the 3 gal tank, and a fair number of them of various sizes. I haven't seen any scuds in the 10 gal tanks. I have populations of tiny crustaceans established in the 10 gal tanks, and I may put some scuds in with them and see how they do. I'm hoping the additional food source will make a positive difference. I have put some in the 3 gal tank and for a few days I see quite a few, but a few days later, I don't see any. If I can raise enough plankton sized crustaceans, I may be able to maintain the scuds on them and FA (plus a little flake fish food, and rolled oats, and bran).