Aqueon Small Aquarium Fish Tank Submersible Mini Flat Heater Up to 5 Gallon Aquariums, 10 Watts

Works great! My betta fish is much happier now that the tank is warm. Its a 2.5 gallon tank amd so far has kept it at about 80 degrees.

I currently use two of these for two 2.5 gallon betta tanks. The most important thing to know about these heaters are that they do not shut off! They continuously heat the tank just like a simple space heater in a room. Eventually the water in the tank will reach a steady temperature. The final temperature of the tank is primarily based off of 1) The size of the tanks and 2) The temperature of the surrounding air. If you keep your room on the cooler side (roughly 66-70 degrees Fahrenheit) this heater should heat a roughly 2.5 gallon tank to a high-70s/low-80s temperature which is perfect for a betta. It could also work for a larger tank in a warmer room. Aqueon also produces 5, 7.5, and 15 watt heaters for different tank parameters.Other notes:- Extremely compact design- One of my heaters runs about 1 degrees F warmer, though this amount of variation isn't an issue for me.

Works

Didn’t work at all. Followed instructions and it never heated the water. That’s too bad cuz it was just the right size. It’s small and doesn’t take too much space. The suction cups worked well. It has a nice sleek look and seems like strong material. It didn’t work to heat tank though.

I purchased this heater when my fish seemed to be getting really sick over the winter. We keep our house really cold during the day, so I figured I would give this a try. 10w for my 1.5gal tank was recommended, saying it would keep the temp about 10 degrees warmer than the room temperature.The first one I received, I put it in a test tank and it heated for maybe an hour and then died. I requested a return instead of a refund, hoping it was just a faulty heater. The second one seems to work much better in that it actually heats up the tank. I do not trust it to keep a steady temperature though. My house is kept at 65 degrees during the day, but the heater seems to keep my tank between 78 and 85, with no apparent reason for the difference. I have to turn my heater off completely when we turn the heat up to 68 degrees at night so it does not get up to 88 degrees (which it did in my test tank). I was going to return this one, but my fish might die before I get my money back to buy a different one, so I am just going to buy a timer instead of plugging and unplugging all day.

Small profile and easy to install in a 2.5 Gal tank. It helps leave alot of space in an already small tank for a betta fish and a snail. I have 4 of these with 3 being used now. They work very well as long as you keep them under water as the instructions say. So far no issues with any of them. It's winter now and it keeps a 2.5 Gal tank at 70 to 73 in a 59 degree room but definitely unplug these in the summer. Sometimes during a water change the will turn on if the water temp is different and take a minute to turn off.

Looks good

My petsmart thermostat was off so I got this. Turns out my petco thermostat was more accurate. During the summer in California I don't need it on. It worked while it was plugged in and would come in handy once the fall and winter hits. Amazon has more accurate photos than petco, otherwise I would had just bought from the store to support then. Petco had an old outdated photo that showed more white paint on it than I would had liked.