shock it
depends on how deep your well is and how high the water is in it
go to your local dealer and purchase a bag of pool shock in one hour it will be clear again If your controller has a Shock or Super Chlorinate setting then put it in super chlorinate and run the filter. You should also add sone algeacide and maintain it.
ratio of chlorine to drinking water ?
Kills bacteria and harmful organisms.
It does not matter if it is an inground or above ground you need to super chlorinate to kill the bad things in the water that you can not see with the naked eye, and have sparkling water the sun will consume or remove the chlorine from the pool if you shock your pool, do it at night when everyone is finished swimming for in the morning you can let people back into the pool to enjoy the clean water, some people just find it easier to just super chlorinate their above ground pools or shock because of the small amount of gallons of water to treat you need to keep the chlorine level up, for if you do not you are asking for problems.
it would eventually shock the fish and kill them
If the fish are an Estuarine species it is possible that they could be slowly and gently converted to live in fresh water. They would however die of shock if they are taken from salt water and suddenly placed in fresh. If they are true marine fish from the Ocean, then they will never live in fresh water no matter what you do.
Test the water, then adjust your Ph to about 7.2. Then chlorinate.
Chlorine is a highly efficient disinfectant and is used to kill disease-causing bacteria in our water.
One pound of salt for every one gallon of fresh water. Also, as the water evaporates, add only fresh water...and slowly! When I kept fish, I would drain half of the remaining water, then mix in the fresh water, then put the mixture back into the tank. This prevents the fish from getting a fresh water shock. The water will evaporate and leave the salt behind, so if you add more salt, it will be too much.
I've read that it was a shock to put them in colder water when they were just in warm water. All you have to do is simply replace the water with the same temperature as the original water.
do some research on them, water temp is the most critical thing for fish, if you place a fish into a cold water system from a warm water system they will go into shock,