After a conversation with TJ last week we thought maybe I should post this question/observation here and see what shakes loose.
About 2 weeks ago I found a large dead bullfrog floating upright in the pond. Pulled him out, not a mark on it. Thought very little about it, then 2 days later I found 2 dead garter snakes on the bank, also without any obvious marks such as inflicted wounds by a Heron. I also noticed a few (3-4) craws floating in shallow rocks, started wondering what the heck was going on.
I've done several water tests with nothing really standing out. Tests were done last week.
The last 3 days I've noticed more and more dead craws up shallow and today I found 2 leopard frogs just floating dead.
All of the craws I've pulled out have what appears to be an algae-like growth on them. Even though the craw is still solid-fresh dead-it looks seriously like algae.
I have not found any dead fish and this spring has shown a lot of active, aggressive, healthy growing/feeding fish.
One key is craws are all about the same size, I would say "large", so I can't help but wonder if it's an end-of-life thing?
The frogs and snakes baffle me though, both look clean and healthy.
The only water parameter I could say is even slightly out of whack is pH at 8.4. Been there since I riprapped entire banks last spring.
Arrowhead coming good as is pickerel weed, softstem bulrush and seeing a few sprouts of sago.
Any ideas, I've got open ears.

I'm totally baffled unless it's some cyanobacteria [which you would see I'd assume] or some kind of reptile/amphibian/crustacean fungus or bacterial infection....basically I'm completely lost. Hopefully Cody or Eric or someone will provide some insight. Sucks Kenny...

Really sorry to hear about your troubles. Wonder if there were some sudden temperature changes that stressed out critters. Maybe all the rainfall -- I assume you've had a lot, like we have down here -- brought in runoff from a recently sprayed field? Just shooting in the dark, hopefully the experts will be able to accurately diagnose the problem.

Tag

My craws have a dark brown algae-looking substance on them - mostly on the bottom half of their bodies...meaning below what would be a lateral line if it were a fish. Actually only about half of them have this somewhat fuzzy thin film. I find that to be normal for older, larger craws. I think the cleaner looking ones have molted it off with their new exo. I'm not sure what's up with the rest of the situation.

We've had less than 3/4" of rain total for the year so far this spring and it's been very mild for the most part. We had a couple of days the temp dropped enough for a little snow but water was mid 40's, no sudden change, still 50-55 daytime temps during that.
I also eliminated my runoff issues by building a berm and a channel around pond. water is totally well supplied other than actual rain but no runoff anymore.
QA, I hadn't thought about the growth on shells during winter with no molting, that would make sense. I worked hard gathering leopard frogs from back in eastern Kansas and I really hate to see those youngsters that are obvious offspring of what I transplanted a few years back dying off.

When I first read the title of the thread, I thought 'aw crap! The gypsies are back in town!' ...but that wouldn't explain the dead crawdads.

I've found a couple dead turtles (small painted, and large Box) over last week. Think they may have been killed by recent cold weather.

Water Test results..
pH 7.3
Nitrates 2.295mg/l
Nitrites-unmeasurable
PO4 (phos) unmeasurable
KH/Alkalinity 8.6dKH-3.0702meq/l-153ppm CaCO3

Tonight at feeding time I can assure all there is nothing apparent affecting fish. Tonight the feedbag was on by large numbers of YP from small to Jumbolicious, Monster Male BG, even some SMB were showing up. GSH were literally flying up on the bank, I believe a true feeding frenzy was taking place. Probably the most activity from the biggest fish I've seen since stocking the pond.

My dogs are the biggest source of wildlife mortality around the pond (raccoons, possums, and a big garter snake). I also have one that goes after my BG when I throw food in the pond. Dives off the dock like a rabid wolf, snapping and growling, and then swims around biting the fish food off the waters surface. I really need to take a video of it.

"Jumbolicious?" That sounds good!!!

32 additional dead craws today, all sizes very few small though.

It would appear I have a case of Saprolignia, I am familiar with this in fish but I've researched and found this to be extremely lethal in certain forms to both terrestrial and aquatic amphibians and crustaceans. However, the cure seems to be an upward trend in temperature. It seems this is most common in spring, coming out of a stressful winter. I can't find literature suggesting an overall pond treatment. I'm a bit surprised I haven't seen fish swimming with this but I did find reference to how it may affect fish differently than other dwellers in the pond.
ewest, I think I need your help.. I'm at a total loss for what to do here. I'll keep looking but treatments I've found refer to individual specimens. (such as my salt treatments I do on each fish I catch before I return it back)

Kenny at least you’ve identified it looks like our hunches were sorta on the right track. Wish I could help but I’ve never experienced this before on the forum.

Probably can only let it run its course. I have been loosing pickerel/tiger frogs for 6 years running now. Just them, nothing else. Assuming it is some kind of pathogen. This year is the first time I haven't had to go around the pond and fish out the dead ones, but quite possibly because I have mink cleaning them up first. I keep finding dead half-eaten frogs on top of the dock, picnic table, and my ADK chairs.