Ducks eat worms and other insects like most birds
yes i think that is how it goes in a ecological pyramid.
Spiders and praying mantis do.
there isn't an insect who feeds on fishes.
Owl
The duck will get sick
A duck that eats fish is known as a "dabbling duck." These ducks primarily feed on plant matter and small invertebrates but may also consume fish occasionally. An example of a dabbling duck that eats fish is the Northern Pintail.
raccon
a lizardfly
grasshopper
Owl
The nightingale eats spiders and ants.
Yes the puma could choke on the duck's bill or the duck could give the puma mercury poisoning after it eats the duck.