Ok, man. Do you really think, that it's normal, that your heater has become the reason of the death of the fish? Where is the 100% guarantee, that the fishes won't die once more time? Have you thought about the natural filter of heater for such situation, like you, when you can not to see the fish for months? My uncle is the fish lover and I know, that he has live rocks, like additional filter (but it can replace the main one if the electricity won't work) and make the water clearer and the area more convenient for fish living. If you haven't even heard about the live rocks, then you can read the article on ARCREEF. Hope you fish won't die this time, take care about them.