i hav the same experience of my fish having pop eyes. wat i did was jus change water everyday for 5days. so far all survive... mine is jus a fowlr tank. mainly angel. i also face some other problem wit my fish like fin rot, bloatted tummy, fungus, mouth swollen and some others. but all i did was to change water. my theory is tat, as long as e fish is eating, i jus keep changin water. i didnt take out e fish as tis might stress the fish more.