Most of the insect larvae and fish you will find in a pond will be either completely or partially Omnivorous.
the water in the pond is not living
Some can be found in pond water but not all.
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.
frog
It depends on the lake and pond. Usually, lakes and ponds are freshwater because they normally have an outlet of some form. In some cases, there is no outlet, allowing salt to accumulate. Some of the saltiest bodies of water on Earth are actually lakes.
rocks, water, soil,
some of them do
No because some other fish eat different things in a pond.
A pond habitat is not just the water, its everything around the water too. THis is becdause everything near the pond use it as a main source for water.
some types of fish and some frogs.
some types of fish and some frogs.
A pond heater is used to keep your pond from freezing solid in the winter. A frozen solid pond is bad for your pool liners, koi, and for some pool structures that may use cement.