Mini Aquarium Heater 25W Small Fish Tank Heater 25 Watt with Free Thermometer Sticker

Surprisingly good. I personally use it with a 5 Gallon tank and temp is pretty accurate. Just plug it in and you’re done. Been like 2 years and it’s still working great, even when I accidentally left it plugged in out of water for an hour, it kept working later on when I put it back into water. Great price for such a solid product.

I recently purchased the DaToo Mini Aquarium Heater 25W for my 3-gallon betta tank, and I couldn’t be happier with it! It’s small, compact, and fits perfectly without taking up too much space in the tank.The heater is preset to 78°F, which is the ideal temperature for bettas, and it keeps the water at a steady, consistent temperature without any fluctuations. I also love that it comes with a free thermometer sticker, making it super easy to monitor the temperature at a glance.Setup was quick and simple, and it started working right away. My betta seems much happier and more active since I started using this heater. If you have a small aquarium, this is the perfect heater—reliable, affordable, and efficient. Highly recommend!

I'm using this for a 3-gallon shrimp tank. It's tiny. It's cute.There is a very belt-and-suspenders approach to being sure this thing is working properly. It lights a little even when it's not heating the water (I expect it's not heating the water when the room is nearly 90 degrees in August). The light is really only visible when the tank is dark and there isn't too much light in the room, but it's a small square by the bottom, just to clearly indicate it is working. I like that assurance. The little thermometer, which is also tiny and out of the way, would be another indicator, again if it weren't August and showing the water temperature in the 80s without the heater. So you can be certain, if there is a problem, you will know.But the ambient room temperature does lead to another point. It's small and I don't think it's that powerful. For me, the room is never going below 70 degrees. I'm in an apartment building with a lot of elderly residents, and the super needs to keep the place warm bordering on hot for them. I need the heater. The water will get too cold for the shrimp without it. But not more than say 10 degrees below their comfort level. If you're thinking a tank in say a garage (I know some people who use that as an office and keep a betta there) and you're prone to reasonably cold winters, then this might not be the thermometer for you.The shrimp seem to think it's a nice platform to sit on. I usually find at least one perched on top.I like especially how deep I can store it and the suction cups keep it firmly in place. If I'm only doing a one gallon water change (they're shrimp -- they have a really low bioload so changing a gallon a week is fine) then I can keep it plugged in while doing the water change and it stays fully submerged the entire time.

I have a large glass bowl that I use as an aquarium for my small tropical fish and I got this heater to use in it because it is only 2-3 gallons in size and this heater is perfect for it. It works great! I have purchased small heaters before and had trouble with them i.e. not really able to control the temperature well, but this one seems to be working great and keeping the temperature right at the correct level for my tropical fish without overheating the small tank. So I am happy with it. It came with a free stick on thermometer which didn't actually work i.e. the temperature would not show on it so I pulled it off the side of the tank to throw it away and it left sticky residue on the outside of the tank which was difficult to remove. I think it was included so you could verify that it was keeping the temperature at the right level. So the small stick on temperature strip was a failure but using a regular thermometer in the tank shows that it is keeping the temperature at the correct level and the heater itself has a little indicator light which shows when the temperature is safe (green) and when it is too hot or cold (red) and that works. So I threw the temperature strip away because it did not work and with some difficulty I finally got it off the side of the tank. It left little sticky bits behind on the glass that I had to scrape off. But the little heater works great and has its own internal safety indicator light where red equals out of safe range and green means it is safe and that does work. But the external strip thermometer didn't work and when I tried to remove it from the outside of the tank it was difficult to get the sticky adhesive off the side of the tank as some of it pulled off the little strip and stuck to the exterior of the tank glass and was difficult to remove from the glass. So I threw the small thermometer strip away as it was useless i.e. no temperature showed on the strip after a full day but the heater itself is great.