No because some other fish eat different things in a pond.
they eat tiny insects that land on the surface of the water and algae
Algae, smaller fishes, fish bait.
Yes
No
They eat the algae all around the pond.
they eat algae and dead fish
They eat mostly algae and other sea plants.
Algae mainly
Yes, it is because without any algae some living animals in the pond would die. Algae can be food for some creatures in the pond. If your pond is just for admiring and not for living creatures, no, it isn't because the algae will take over the pond and no living creature is in it to eat the algae.
algae or maybe died things
Yes Sometimes
Pond scum is composed of algae; it does not eat, it grows by means of photosynthesis.