Welcome to our community. Okay, we will need you to provide test results for water tests, ammonia, nitrite, nitrate and the pH. A photograph would also be very helpful.
Have you got some testing kits? We recommend the liquid tests rather than the strips. You can buy individual testing kits, or you can buy a master kits which has them all. To be quite honest, anyone who keeps fish should automatically have one of these kits at their disposal.
Could you also tell us how big your tank is, and what sort of filtration you are using.
If you can get back to us with some information, I'm sure we can try and help you.