Answer:
The population of these fish will decrease, because they will end up dying from lack of oxygen.
Step-by-step explanation:
The low concentration of oxygen in the water is very harmful to fish.
Fish, when exposed to a low concentration of oxygen in the water, even for a short period of time, do not face so many problems as long as other water quality parameters such as pH, ammonia, and nitrite are at acceptable levels. However, a permanent value below 60% saturation is intended to cause problems in fish health. Most survive a few days with a saturation of 40%, but if the oxygen concentration drops quickly, the fish will begin to feel the effects of the lack of oxygen and will eventually die.