My fish had all been great up until a few days ago.My two clowns have white spot and i treated them with Interpet Anti White Spot.It says to take the black carbon filter out beforte treatment.The water looks really stagnant now and my two clowns have gone bright red around the gills,They are really struggling to breathe.The rest of the fish are all at the top gasping at bubbles.....What can i do, please help!!