At the corner of happy and healthy

Healthy fish are happy fish so I'll tell you the behaviors of the fish when they are healthy and unhealthy. In the tank we've noticed  that if the fish are hungry, they swim more to the bottom of the tank. When they are dying they start swimming upside down and in circles, unless it's out of water then they flop around. In the winter in a pond if you don't have a bubbler the fish won't get enough oxygen and they will die. The equipment in the tank may be dangerous to the fish if it breaks. The equipment could electrocute the fish because everyone knows water and electricity do not mix well. Ammonia is another danger to the fish if the owner does not clean the tank, the fish will get ammonia poisoning from the poop and germs in the tank, and then they will die.