I have had 3 goldfish die after a 3" hybrid bluegill died over the past three days. In my 150 gallon ft, ph is up to 8.7! Amm =.3, nitrites=0, nitrates=40 temp at 76f. Could not see anything on the bluegill unusual, but the goldfish have patches of missing scales. The gf are laying low mostly and when they move, they slightly slurp at the surface. That might be a response to seeing me and expecting food.
I followed some advice on cleaning airstones by soaking in hydrogen peroxide just before this trouble began. I soaked 2 of my four airstones then ran air through them in a glass of tap water before returning them to the tank. Would the hydrogen peroxide even in the most diluted form cause so much trouble? I also pulled and cleaned the pump and hoses at the same time 4 days ago. Did my actions bring too much stress? Their bellies are slightly bloated. When they die, they dont go belly up, just laying sideways. I cooked and added some peas and brocolli today in case they are constipated. I might have also,been overfeeding
Any input will help, thanks in advance