An ecosystem is defined as a dynamic system of biotic and abiotic components and there is a continuous flow of energy between the different components. Its two main components are:
(i) Biotic component/living organisms
(ii) Abiotic component/physical factors
An aquarium needs to be cleaned regularly because it is an artificial and incomplete ecosystem in which natural decomposers are absent and the water is stagnant. Thus, water do not clean itself in an aquarium.
