Other than frogs I have purposely tossed into the water, I have never seen a bass eat a frog. I am not saying they don't, but with the hundreds of hours I have spent on the water I figured I'd have seen that by now. I did have a smallie cough up a leopard frog once when I got it in the boat. I don't think having frogs around your pond is a bad thing, but in the end I doubt they add much than 1% or less of the forage percentage of bass in a pond even in ponds chock full of frog habitat and frogs.