i have a goldfish....is about 5 inches long and it has been acting weird for a couple of days. it used to be really active but now he just hides behind my filter intake tube. he seems to be stressed for some reason cuz he is always opening and closing his mouth. also i tried feeding him but he wouldnt take the food amd he always used to eat a lot.i dont understand whats happening. i also have another goldfish same size and he seems to be doing fine. he doesnt seem to have any itch. and i dont know what else he could have.