Hi guys! I have this case were my friend arowana died. It all started when I came to feed the fish because my friend went on vacation so I have to take care of it. It was the 2nd time I feed the fish because I was checking on it every 2 days, the 2nd time I had notice that there were broken glass scattered on the sand floor. I quickly pulled the plug for the water heater and scoop the glass out of the water. I don't know when the fish broke the heater, because if it was after I visited, then it has been 2 days that the water heater is plugged in maybe electrocuting the arowana. now after the discovery of the broken heater, the fish still ate when I came back for it after 2 days, so I checked everything and brought a new heater for the fish, after 2 days I came back and shock to discover the arowana is dead and floating in the tank. My question is what cause the death of the arowana? 1. Did the fish died of electrocution? if so why did it take a long time for it to take effect? 2. Did the arowana accidentally swallowed some of the glass while it was swallowing the food from the bottom floor of the tank? because I'm not 100% sure that I scooped up all the glass out, I was thinking maybe some tiny glass got inhaled while swallowing the food and may cause digestion or internal problem with the arowana. 3. Are there components on the water heater that may cause water be harmful and even fatal to fish? I had read that the water heater has a component called polymeric filler and I googled polymeric and it says its harmful to fish. Need to know if this is true and if any other component of the heater can cause water problems. I need to explain to my friend when he gets back the cause of the arowana death. thank in advance guys.