Review on 🐠 SZELAM 25W Smart Mini Aquarium Heater: Submersible Betta Fish Tank Thermostat for Efficient Water Temperature Control, Anti-Explosion & Energy-Saving Warmer by Matt Duffy

Very slim design. Even in my small round aquarium it almost disappears. The indicator light is a reassuring feature. I love that I can see the temperature and what the heater is doing thanks to the light. My fish don't care. He struggles with the glass thermometer, but the heater is fine. Also, it hugs the glass snugly so it doesn't stand a chance of snagging on it. This is a heater review, but also something I've learned the hard way and I hope someone can learn from it. I have a 3.3 gallon Topffin Bettaflo round tank. It is 10 inches high and 10 inches at its widest point. The filter is a substrate, the reversing tower is right in the middle of the tank, so there is not much space inside. The fact is that heat does not radiate through the glass. So when the lid is closed it's like a thermos inside and the temperature rose to 86° with my previously purchased 15 watt Petsmart heater. It's just a few degrees of cooked fish. To be honest, I thought aquariums were supposed to be relaxing. This tank annoys me because of the difficulty in maintaining temperature. This is similar to LowE glass in that the thermometer rod does not indicate temperature. As for the heater itself, it's amazing and after a few days of adjusting it now holds a consistent 82 degrees in my tank. A clear recommendation!