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

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.

Bought this last year and it's still working great despite not being treated that well — discolored from tannins and algae in my tank, left on with the top unsumerged a few times while doing water changes, and accidentally left outside in the scorching heat (90-100F weather) for a couple weeks. Still keeps my 5 gal at a steady temperature. Used to be 78F, apparently 82F this summer, though I think that might be my thermometer's fault; the water feels fine. Only minor hiccup is that the cord is a little short, but I use an extension cord on the table, so it's not a problem.

I love this heater because no matter what my temperature is in my apartment the fish tank stays exactly at 76.5. I have other heaters where it gets too hot if it gets too hot in the apartment. This heater is perfect for a 3 to 5 gallon beta tank. I haven’t tried it with a 10 gallon but I imagine it would even work there.

I'm on day 2 with this is my tank.. it holds the water temp between 78°F and 80°F. So far my issue is with the suction cup not holding to the side of the fish tank. I've had to place it back on the side of the tank twice already. I'm really hoping it doesn't bust, as I've been reading several reviews that the glass tube busts and one has busted the fish tank 😖 if it keeps coming off the side of my tank, I'm going to have to look for a more expensive heater for my black orchid betta.

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.

This thermometer works great for our little 5 gallon tank. Easy to install and use. Would recommend.

As most of you know a heater is a necessity for most if not all aquariums and I recently got into fish and wanted to start off easy so as a beginner does I got myself a betta. My tank is 5 gallons and full of live plants and my betta is thriving. The heater heats up surprisingly well and it comes with a preset temp already so no need to haggle with the heater at all just plug and place into your aquarium. It doesn't take much space and it indicates when it's at the ideal temp with a green light. I would rate this a bit higher but I did recieve mine without a suction cup but have ordered a replacement but besides that would reccomend.

Perfect size for our 3.6 gal betta tank. Easy to install and use. Seems to function as it should bcus our tank always stays around 78 degrees. It's preset for 78 degrees. So only turns on when water falls below 78, auto shuts off when tank reaches 78. Seems to be accurate bcus our tanks always reads around 78. Quality seems good. I only wish there was a light or better one if there is one that let's me know it's on, so I know it's working. Worth the price. Great for small tanks.