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

Have had it plugged in and running for a few days in my 1.5-gallon tank, and it is working great! The red light turns on when heating; green light when it's at temperature (~78° F), which I've been monitoring via a digital thermometer (temperature seems to stay right between 77.5° and 78.5°). I'm not able to adjust the temperature, but 78° is right around the temperature I'll be needing, anyhow. This heater keeps the temperature in the target range, whereas the 10W heater that came with the tank couldn't, as the water was always way too cold previously. The included thermal tape thermometer kind of works, but is not very accurate and it's really hard to discern the colors; it's nice to have, but I'd recommend something else if you need more temperature accuracy than ±5° and you have a larger tank or a colder room. Also, the suction cup fits the heater well and is nice and soft, holding to the plastic tank really well! (I was a little impressed with that, actually.) Read more

Works well for my 5 gallon tank. Keeps my fish warm in the winter and snails seem to like to hang out around it. I have the thermometer on the other side and it keeps it at perfect temperature so I know it’s working through throughout the tank. Read more

Great heater. Bought it in a hurry without much research and I'm really happy with it. I have it in a 5 gallon tank and it keeps it at around 74-78 for the most part. It fits in the back of my tank well so it is concealed, keeps it at an even regular temp even with our house temps fluctuating, and I've had no issues with it. Easy to use just plug and go. Read more

I have ordered a ton of these. So far, most of them seem to work pretty well. They keep the tanks around 78F, give or take a tiny bit. You can’t adjust the temperature since it’s preset. I’d like it if they came in a smaller size and also if they had a shatter proof option. These are glass without an outer casing so they might shatter if they overheat. These are not mini but they’re not huge. They’ll work for a 5 gallon tank or bigger. Don’t use these in anything under 5 gallons. They’re too big for that and might overheat. The heaters are easy to use. Just attach the suction cup, place in tank under water, and plug them in. Read more

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. Read more

My Betta tank is in my poorly designed bedroom, heating vent at the top of the wall around the corner from the main part of the room so it is always cold in here. I was having a hard time keeping the water temperature at a good level so I ordered this little heater. Within 15 minutes of installing it, the water temperature rose to 78 degrees and is staying there. Very easy to read, when it lights red it is warming the water, when it lights green the water is at the pre-set temperature of 78 degrees so you don't have to worry about adjusting it or turning off/on. Very affordable, small so it fits into a small tank, good quality materials, comes with a temperature strip. Definitely recommend! Read more

Keeps our betta's 5 gallon tank at 78-80.7 degrees depending on our room temperature. Even after a 30-40% water change it doesn't struggle to bring the water temp back to perfect. It was plug and play out of the box. The thermometer strip that came with it never worked to tell the temperature but I was using a separate digital thermometer anyways. Awesome price too!! Read more