====Fish and Water problem====

There could be several versions of it but the one I am referring to is following:

A fish happily lives in a pond with fresh water. One day a scientist decided to understand how the chemical composition of water will affect the behavior of the fish. So he added an evil chemical which does not change the refractive index of water as fish can sense it but increase the viscosity of it.

Poor fish could not understand why it is not able to swim normally as the water is more resistive now. With time, it could not survive due to the lack of food.

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It is an imaginary experiment with several assumptions:  
	
	- The chemical should not change anything fish can sense.
	- No poison: It should not kill the fish
	- Fish can only die because of itself no direct external cause