Instruct: Classify Amazon reviews into positive or negative sentiment
Query: overheats - avoid this heater

I have one of these that came with the aquarium. It is overheating now. I have been wracking my brain trying to figure out what's going on then I decided to come to Amazon to see if there were any negative experiences... and boy are there! I am gonna order a new one. Thanks, amazon for having useful reviews, and thanks fellow reviewers for letting me know the heater is bad. You saved my fish.The negative reviews are correct here, I am afraid. I'd never buy this heater. Caveat emptor!