Question

we do not clean ponds and lake but an aquarium needs to clean why?

Answer 1

In the ponds and lake the wastes of fishes gets settled and decomposes in the soil under the water.Also the area of a lake or a pond is larger than the aquarium.

Moreover, the aquarium is made of neither of glass or synthetic materials
which cannot decompose the wastes of the fishes at last the water becomes cloudy and dirty even the fishes can die. So to prevent it, we need to clean the water.




HOPE it helps

Answer 2

Answer:

An aquarium is an artificial and incomplete ecosystem in contrast to a pond/lake which are natural, self-sustaining and complete ecosystems. The abiotic components are not supplied naturally to the aquarium.