Please help. We have a sick goldfish. About three years old, is breathing very slow, hiding in the castle in the tank. Was curled in a "C" shape last night but is now straightened out. Does anyone know what is wrong?
For us to properly help you we need a brief description of your set up, tank inhabitants, cleaning routines, and todays water test results. If you do not have test kits most local LFS will test water for you. Mandatory readings include pH and nitrates- ammonia and nitrites would possibly help as well.
In the meantime, there is very little that wouldn't be helped by a nice 50% water change.
We need much more info, specifically tank size, amount of fish in the tank, is it a new setup, filter info, and water readings (as already mentioned). Hope you get these messages quickly so we can begin to help you.