Science Homework Help

I’m working on a chemistry writing question and need an explanation and answer to help me learn.

A person preparing a fish tank uses pre-boiled (and then cooled) water to fill it. When the fish is put into the tank, it dies. In details, explain this using your knowledge of solubility of gases in water. Give an example of gases in water that you see in your everyday life (other than carbonated drinks and soda).