The thing is yesterday after I did water changes I add water conditioner and Epsom salt.You will probably need to send a sample of your well water off for testing. Check online for Water Testing in your area. Find a company that does a full set of tests including agricultural chemicals, heavy metals and anything else you or they can think of. Until then you should probably filter the well water through carbon to help remove anything that might be in it. Floating plants can help too because they can remove some of the things in the water.
You can buy big bags of carbon and put it into a box filter or even buy an inline water filter with a carbon cartridge. The carbon would help to remove any chemicals that might be in the water.
If you do buy carbon, try to get "Activated Carbon" or "Highly Activated Carbon". These are better than normal Carbon.
I'm not sure what the GH of the water is, but if it is below 200ppm, you could add some mineral salts to the water. Some chemicals are less toxic in hard water and the goldfish and livebearers might be less affected.
I though epsom salt is like pool salt or rock salt I added the wrong thing then...You shouldn't need water conditioner unless there is chlorine/ chloramine in the well water, and that is unlikely.
If you added too much Epsom salts, it could harm the fish. And if the Epsom salts were industrial grade, not food grade, there could have been something else in with it.
Everytime my fishes died I feel sad for about a weeks, I feel like its all my fault. I suffer from Ocd even more because of this. I cant even sleep well.Small amounts of Epsom salts are fine but if you add too much, it can harm the fish.
Keeping fish is a learning experience. I lost count of how many fish I have killed over the years. And everyone who keeps fish loses them so don't feel too bad. Just learn from the mistakes and try not to make them again.
Thanks Colin, I lose count how many times I cries of losing my guppies.The fact you feel sad about losing your fish means you care about them. When you no longer care about them, then it's time to be concerned.
In the mean time, learn as much as you can and just try to do your best. And if you aren't sure about something, just ask.