Answer:
1. the rocks at the bottom of the aquarium
2.the fish and maybe the plants (if you use live plants)
3. fish interact with there no living things like how one would hide in the grass or something like that.
4. decorations (like a cave or fake house, tho the aquarium its self is a home)
5.they would die, and rot.
Explanation:
rocks are nonliving
fish are living things and so are plants
fish can hide in the plants
the fish can "live" in the decorations, but the aquarium itself is its home.
if something reaches the end of its life span it dies.