How is the life of organisms …

Almost all types of water pollutants affect the life forms living in the water. The pollutants encourage the growth of some life forms and can harm the growth of other life forms. This affects the balance between various organisms that persists in that system (ecosystem). With the increase in the amount of organic wastes in water, bacteria multiply very rapidly thus using up the available oxygen. The lack of oxygen hence caused kills the fish and other aquatic animals.
Aquatic organisms are used to a certain range of temperature in the water body where they live, a sudden marked change in this temperature can be very dangerous for them (they are cold blooded animals), e.g., it affects breeding of aquatic animals. The eggs and larvae of various animals are particularly susceptible to temperature changes.