No idea, they were sold in bags at the LFS. I'm no frog expert. Here is a crappy photo of one. As far as I know, they hate water. Keeps trying to crawl up the small 5g tank wall. Can't really blame them since they know they are gonna be food soon.
I'm not sure. It looks too thick top-to-bottom to be an African Dwarf Frog, they're generally kind of flat and they're totally aquatic.
As far as pollution goes, many are the first things to go, but as far as parasites go I don't have a clue. I haven't kept amphibians since shortly after high school when my 9 year old toad died.
For me personally , i feed my polys, massivore and prawns, i use to give them feeders but i have grown to love them too much now and the risk is too high, and the effort of keeping feeds for two weeks quarantine. I believe that pellets are much safe and easier for my life style.
I like to feed a diversity of foods, sometimes live foods included.
I oversee a large aquatic fish lab, and almost everything either gets bait minnows, tadpoles, worms or something of the meaty nature. I think that natural foods are essential, and many people will tell you that all carnivorous fish need some "whole foods" in their diet.
Frogs are safe, their tadpole stage is entirely herbivorous and usually its sold as feeders when they grow legs, not much parasites infest vegetation. They are propably crab eating frogs if small, larger ones are bullfrogs. How do you get them to eat floating pellets?