Review on 🐠 DaToo Mini Aquarium Heater 25W: Small Fish Tank Heater with Free Thermometer Sticker - Efficient Heating for 25 Watt Aqua Environments by Michael Caldwell

I bought my first Bette Fish and did a deep dive into reading and learning proper care and handling. I bought this heater because it said: Application: 1 to 5 gallon aquarium; maintains a constant water temperature of 78 degrees. My aquarium has 1.6 liters. The water temperature is a stable 76 degrees without heating. Installing the heater and temperature sensor was easy. After plugging in and running, I looked away from the ball and was alerted to the reservoir when my daughter said the water had risen to 90 degrees! We made fish soup! I didn't know what to do with the fish. We turned off the heat and gradually let the water return to room temperature of 76 degrees. Rather than electrocuting the fish and adding cold water for instant cooling. Maybe I have a defective device. My tip: When buying, just pay close attention to the water temperature when you switch it on for the first time.