Question

Aquarium requires regular cleaning whereas lakes normally do not why

Answer 1

Answer:

Because they are inhabitate of dirty water . On the other hand we can say that they are unfamiliar with the aquatic fish.

Answer 2

Answer:

Normally a lake has more diverse forms of life and hence a larger number of food chains. This leads to natural cleaning. Thus, the ecosystem is more stable. The aquarium has a very limited number of food chains and unable to sustain itself. Bu, sometimes there is excessive growth of algae in lake. Then it also needs to be cleaned.