Ecosystem is the structural and functional unit of biosphere, comprising of all the interacting organisms in an area together with the non-living constituents of the environment.
Two main components of ecosystem are :
(i) Biotic component
(ii) Abiotic component
An aquarium is an artificial and incomplete ecosystem compared to pond or lakes which are natural, self-sustaining and complete ecosystem where there is a perfect recycling of materials.
Cleaning of aquarium is necessary because of :
(i) Absence of natural decomposer.
(ii) Stagnancy of water.
