Jim these are indeed the 'toad poles' of the American Toad. Yours are almost at the exact stage as the ones in my pond. Google what the adult male and female american toad look like. They all make a ruckus of calls on spring nights with air temps hit a certain point. They all then meet in the water (even though they spend their life on land) They carouse, compete, then the smaller male clings to the larger females back while eggs are laid and fertilized. Big strings of eggs lay on the bottom for about another week. The strands get larger and fuzzier as they expand and then one day there are zillions of little black toads. I think Azteca just posted a video of the little critters.

I have never had any fish try to eat them. Remember LMB eat tadpoles and frogs but these are NOT frogs, they are toads. Perhaps they release some substance that warns critters to not eat them which is wild since LMB will try to eat ANYTHING.

I always want to rake out the fall leaves and left over algae this time of year but I can't once the toad mating begins for fear of raking out the toad egg strands or later the toads tinies themselves. They do an AWESOME job of eating everything on the bottom in the shallows. They put a big dent in my shallow water algae. The bottom goes from nasty brown to clean sand by the time they are done. Then slowly they grow legs and one day they all crawl out of the pond together. If you catch this mass exodus you will see the grass moving with millions of tiny toads struggling to work their way through the grass towards the woods. They then disappear in the woods the rest of the year till that magic warm night in the spring when they all jump back in your pond!