I cleaned the tank yesterday, and they are usually fine. One of the fish keeps floating to the top upside down, and if I push it down, it floats right back up. What's wrong with it? Is it dying? What should I do?
Did you use a water conditioner when you cleaned the tank? The chlorine and heavy metals in tap water can be deadly to fish, although some have a higher tolerance to it than others. I'm sorry to say that I think your fish is dying or might already be dead. Watch his gills to see if they are moving to find out for sure.