Tetra Submersible Heaters – Occasionally They Malfunction
Two weeks ago I was feeding the fish their morning food. As I moved down to feed the two 10 gallon tanks I saw a dead fish. Removing the glass cover I saw another dead tetra. I put my hand in the tank and the water was hot. The heater had malfunctioned. I had one large marble angelfish left alive in the whole tank. I quickly got a plastic pitcher and put some water from the 50 gal into it along with some water from the hot tank. I moved the angel into the pitcher. I took the angel to the tank upstairs to the 20 gallon hex. I squirted some water conditioner into the tank and poured the angel into the new tank and prayed for the best. The angel sank to the bottom and stayed there for the next 40 min.
The heater in question was new and still under warranty. I keep my receipts for purchases and so I was able to exchange the heater at Walmart, where I had purchased it. I think in my 35 years of keeping fish this is only about the 2nd brand new heater that has ever malfunctioned in this way.
I ended up losing 2 Juli Cory cats, 1 Bleeding Heart and 3 Serape Tetra (currently being called Red Minor Tetra in the shops, I think). There is really nothing you can do in this situation it is just one of the many things that Aquarist learn to accept. I will clean it out and start over.