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

This was perfect for our travel tank. We took our beta fish with us on our camping trip and he didn't seem to mind the difference. The heater worked and held a steady 78 degrees the whole time. The price is perfect for a travel tank scenario. I would recommend this one to anyone with a smaller tank or traveling with their pets.

Alright, fellow fish fanatics, gather 'round because I'm about to spill the tea on this Mini Aquarium Heater. I've got a 5.5-gallon tank that's basically the underwater equivalent of a studio apartment in NYC—cozy, but every inch counts. Finding a heater that doesn't turn my tank into a tropical hot tub has been a JOURNEY. But this little heater? Oh, honey, it's the Beyoncé of aquarium accessories.First off, let's talk consistency. This thing is like a Swiss watch, but for fish. I swear, it's got my tank water chilling at a solid 80°F. My fish are practically doing the tango, they're so happy with the stable temps. I even caught my snail giving it a little nod of approval.And the thermometer sticker? Okay, it's not exactly NASA-level tech, but it gets the job done. Plus, it's idiot-proof, which is crucial because, let's be honest, sometimes I feel like I'm just winging this whole fish-keeping thing. I stuck it on, and now I can glance over and make sure my aquatic pals aren't boiling or freezing.So, if you're tired of playing thermostat roulette with your fish tank, do yourself (and your fish) a favor and grab this heater. It's reliable, easy to use, and might just make you the coolest fish parent on the block. Trust me, your fish will thank you. They might even start paying rent. (Okay, maybe not, but a fish mon can dream, right?)

My wife has a couple of three to five gallon aquariums that she has show guppies and amano shrimp in one and an outstanding betta in another and keeping the temperature at the correct point consistently is very important. We've compared them with manual thermometers and they are very accurate. They are solidly built and very simple to slide down into the space where the pump and filter are and they stay in place nicely with the included suction cups. There's no fiddling with a manual thermostat - just plug and play, as they say. We've used these for years and definitely recommend them.

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.

I have a DaToo magnetic algae scrubber that I really like so when my old heater started RUSTING I needed a new one, and found this one for a whopping less than $7. I had a 50w before, but my tank is only five gallons so I opted for the less powerful 25w and it does the job easily. I set it up next to the filter flow so it heats evenly. For the price you really can’t beat it.

I have been keeping freshwater aquariums on and off for almost 30 yrs. Heaters have always been the same tech they are now. The BIG takeaway is to keep them cool and constantly sampling flowing water. I have ALWAYS set mine up by the pump outflow and kept them completely submerged. DO NOT keep them plugged in while changing water. This lowers overheating and temperature component shock which leads to a lot of the issues seen in the reviews here. If you have a betta in a setup with no water flow... do not get a heater until you have an actual tank setup. STOP putting these in bowls and expecting them not to blow up.Temperature accuracy and what I have learned with this unit... I keep mine in the pseudo sump unit in the 5 gallon kit I bought. This way water is constantly flowing around the unit. I have an air stone in this same compartment and when it is running it cools the unit more which lead to it running between 80 F - 78 F. When the bubbler is off it cycles and stays a consistent 78 F. So, over agitation can lead to the unit sampling too cool and cycling more. So, I have put my bubbler on a timer and do spaced out 30 min cycles throughout the day. This has resolved the issue with this unit. It needs gentle water flow for accurate sampling and heating. Over agitation can lead to it falsely reading the water as cooler leading to the varied warmer temps.