Leopard frogs are not native to your area. Don't get them.
Where I live we have thousands of leopard frogs. They are out in the cold, they are out in the heat, they are out in drough and in floods. They breed prolificly and are voracious eaters. They will survive in your yard and they will spread and devestate local wildlife. I don't care if the president told you that you could buy one. It doesn't mean its safe for the environment.
You pond is overstocked anyway.
You have to many goldfish that you don't take care of well, goldfish aren't designed to eat mud, or larva. They eat insects and smaller fish. Mud and larva don't have the protein and nutrients they need to sustain their body size. How about you eat one cracker everyday and see how you feel in a week.
I have a feeling you will get a koi. Which you will underfeed and stunt. It will live a horrible life.
You will also probably just go get a frog from you lfs still and ignore those that try to explain things to you. Have fun wrecking the environment. People like you are the reason we have so many stupid laws in this country. Thank you. I hope you have fun ruining the environment.
Oh and as a side note, If you decide to keep a frog indoors don't get a leopard, they get to big for 100+ gallon tanks. They can leap 6+ feet and hurt themselves on the glass. I suggest a tree frog or a Fire bellied toad.
Take the advice of others when you ask for it, don't just ignore it.