Review on hygger 50W Mini Submersible Digital Display Aquarium Heater: Compact, Fast Heating & Thermoregulation for 🐠 Small Fish Tanks, with External Controller & Built-in Thermometer - Ideal for Betta and Turtle Tanks by Audrey Ortiz

I would like to give -5. I don't normally write negative reviews but I have to as I am very disappointed with the performance of this product. I bought a 50w mini heater for my 1.7 gallon aquarium which houses a male cockatiel named Poseidon. In the evening I set the heating to 22 degrees. Normally the water temperature for bettas is between 22 and 25 degrees. I went to eat with my sister and when I came back at 9pm everything was fine. My rooster was an excellent swimmer and, as always, cooled off on his rock. My cat woke me up at 4am. About a minute after waking up, I noticed that my fish was panting and swimming heavily and showing red stress flags. As I investigated the matter, I noticed that the water was hot to the touch. I quickly removed the heater, which read 76 F on its digital display. I used a thermometer to measure the actual temperature; it read 100 F. I immediately started doing about 20% cold water changes to try to even out the temperature while being careful not to further stress him. After 15 minutes of water changes, he felt better and showed no signs of stress. The owner's manual and product description state that this is the "ideal heater" for a 0-13 gallon aquarium. I've worked with different heaters when I've had fish in a 5.5 gallon tank and have NEVER had such an experience. Unfortunately I had to downsize the aquarium due to the downsizing of the house. However, I was just looking for a small heater that would work well for my aquarium. Also, the heater's size is quite bulky for what is advertised as being able to be in tanks under 6 gallons. I am currently looking for 10W mini heaters. Luckily my 3 year old betta didn't die but I will not be buying from this company or seller again.