Hi I have a 55 gallon tank with angelfish, tetras, mollies, rapheal catfish, a couple danios anyway my question is my tank is present to 78 degrees is that too high??? I actually just bought a new heater that is present to 76 degrees so when it comes I'm going to switch it if I have too and also will it stress the fish if I bring the temp down from 78.6 degrees to 76.5 degrees cuz when I unplug the 78 heater to the 76 heater the temp in my tank will drop slowly but will this hurt the fish at all??? Please someone get back to me