Question
twice during the last week i have seen  one of the larger frogs astride my 5 inch goldfish. First time along its back half, this time on its head and front half. i have tried to prod the frog but it will not go- the goldfish appears to be swimming fast trying to dislodge it. I think the fish is losing the battle

Answer
Where do you live that your frogs are already in the mating mood?  Male frogs prefer to amplex with a female of their species but if they can't find one, they will amplex with a male frog, a frog of another species, or sometimes something that's not even a frog like your poor fish!  Do you know what species of frog that you have?  How big is he?  Amplexing is where the male grabs on tight around the waste of preferably a female of the same species.  The grabbing on makes sure he's there to release milt when she releases her eggs.  Sometimes, the squeezing helps squeeze out the eggs too.  When a male frog is amplexing, he kind of goes into a zombie state and will hold on really, really tight.  I've tried to pry male frogs off of other frogs including a male wood frog on a male green frog.  In that case, it doesn't work to just pull, push, etc.  I was cleaning that pond and put them in a bucket but I really don't remember what made him let go.  If gentle prodding doesn't work, I'm not sure how to get your male frog to let go of the poor goldfish without hurting one or both of them.  Have you tried slipping, moving the frog down the goldfish or is it just too stuck?  I wish I had an idea that came to mind right now but I don't.  If you figure something out, let me know so I can help the next person who might have this question.  I wonder if you put a fake frog in the pond if he would grab onto that?  I think they are just so single minded that he thinks he found his prize and isn't letting go.

Good luck!