Bests & Worsts Reviews from Amazon

DANGER - While this worked great for a while (from about Aug 2014 through Jan 2015), it can fail in a catastrophic way that results in continuous heating. I've attached a photo of the sad scene I found one morning... the heater thermostat apparently failed and the water temps in the tank reached 102ºF overnight. I suspect you'll have the same risks with ANY heater—especially inexpensive ones. Best protection is to have a thermometer with an alarm, such as the "General Tools AQ150 Digital Aquarium Thermometer" amazon.com/gp/product/B00M9T7ZF8 While it worked, this heater did function as advertised. I've since replaced it with a different model—plus the temperature alarm referenced above. The fish has also been replaced, but it was a preventable, sad morning!