Question from a novice pond owner in Ohio. 1/3 acre pond first summer at full pool. Stocked w/ SMB, YP, RES, FH.
No aeration. 18"+ visibility. Added blue dye a month ago as FA was starting to grow. Water looks very healthy, no odor, etc. I've been swimming it in weekly all summer.

I have norther green frogs and a couple bullfrogs that took up residents and spawned this spring. Pond was full of tadpoles. Over the last three weeks I'm noticing daily tadpole deaths. My fish seem to be doing fine other than two floater YP found two weeks apart. These were stocked in April, so...? I'm not that concerned about the YP floaters.

I fished for the first time and caught two SMB in less than 30 minutes, that had very healthy appearances and considerable growth rates from their size at stocking in April. FH are reproducing like rabbits as FH fry is all over the pond.

So my question, any guesses on why the die off of tadpoles? Don't get me wrong, I'm happy not every tadpole that was in the pond is going to mature... as I'd be overrun with frogs. So is this just a natural occurrence or do I need to look deeper?

Could be disease. I know there is concern about fungal infections spreading globally. Could also be localized oxygen deficit near shore?

https://en.wikipedia.org/wiki/Chytridiomycosis

The first year at my pond, without gamefish, produced thousands of tadpoles of many species...mostly bullfrog. It was not uncommon to see a few floating tadpoles (dead or dying), maybe not daily, but close. You are probably seeing the results of the normal mortality rate.

Also, with the existence of predators in your pond, tadpoles are not a favorite meal and the tadpoles may be being hit and spit out left to suffer and die. This is just a guess.

Side Note: I thought for sure we would be sweeping up frogs off the drive way, out of the shop, and mowing more frogs than grass, but they seem to leave the pond and disappear very effectively. I might have noticed a few more baby toads in the front yard than normal, but, all in all, their exodus was mostly unnoticed. They might lose their bad taste as they turn to hopping and become bird, snake, raccoon, and possum meals as well.

I have a strange year with absolutely no bullfrog tadpoles in the spring. Went into the fall with tons of them, nothing in the spring. Plenty of toad tadpoles. I still don't even see this year's hatch-lings so I am a little worried.

What we did have is several mink, and I can only assume those little buggers cleaned house under the ice when the frogs and tadpoles were in a stupor.

The fungus problems seem to not bother northern frogs/toads as much. I don't know why, could be the cold keeps the fungus at bay.

I did have a disease run through the pond killing off pickerel frogs two years ago, and that was sad, but I still see plenty of smaller ones hopping through the grass.