Marina Betta Fish 8W Submersible Heater - For Fish Tank Aquariums up to 1.5 US Gallons (5 L)

I was very iffy about getting a heater for my betta as I did not want to deal with the nightmare of it cooking my betta which I always worried about. I have my betta in a 2 gallon glass bowl and despite keeping him in the warmest room in our house during the winter and the room being very small. Despite all this his water was so chilly and he was very inactive and not eating much (my betta was always very active and very curious and very hungry). I decided I needed to get a heater and this heater being very small (so as to not take up much room) and being specifically for bettas I figured I'd give it a try. The water is now a toasty 79 degrees and my betta is once again very active, very healthy, and his colors are brighter and his fins flaied out. It took him just a few days to perk up and get back to his normal self after putting in the heater. Now, PLEASE READ THE FOLLOWING. These are very important points.1. Use a thermometer. I used this one: Marina Floating Thermometer with Suction Cup. I got it off amazon and it is small, does not take up much room (just the bottom needs to be subermged) and is accurate. YOU MUST HAVE A THERMOMETER. I highly recommend that one.2. DO NOT USE THIS IN A 1/2 BOWL. Despite it saying it can be used for this in the directions do NOT use this. It will heat the water up wayyy too much and cook your fish. If you are using a half a gallon bowl I am begging you to please upgrade to at least a one gallon bowl. A betta can barely turn a 360 in a half a gallon bowl and they need exercise to stay healthy and well. I recommend at least a two gallon bowl/tank. They are very cheap off amazon OR go to your local craft store and combined with a coupon you can get a glass bowl in 2 or 3 or 1 gallon for less than 10 dollars (check out michaels!), very cheap and your betta will be much happier and you don't have to worry about the cost.3. IF you are using a 1 gallon or 1.5 gallon bowl/tank get a wall timer and set it so that it goes on and off every hour (1 hour on 1 off 1 on etc.). It will get too hot if you do not do this.This works perfectly with my 2 gallon bowl/tank and it would work up to a 3 gallon tank/bowl (ignore the directions) but I wouldn't use it for more than 3 gallons. The way you clean it is to soak it for about 15 minutes or more in a mixture of vinegar and water. Do NOT use soap on it or on anything you put in your fish tank. Soap leaves a residue that will make your fish sick. Using a small amount of vinegar and hot water to clean things works well. When you first put the heater in the bowl/tank wait 20 min before turning on to allow the heater to adjust to the current water temperature and make sure when removing it to unplug it and then leave sometime for it to cool off. To be noted it took about 5-6 hours for the heater to bring my 2 gallons of water to its set 79 degrees.I really recommend this heater and it works perfectly for me. The only complaint I would have is that it is a very small heater and $15 is a little pricey. I have gotten heater for 10 gallon tanks for cheaper. Good product.

This heater is excellent! I've used it for 3 months now. I have a 1 gallon tank and it works great with my beta. He loves it and rests atop it whenever he wants to get warmer.***Important things to know:***This heater does NOT shut off by itself. It says it will reach a preset temperature, but it means the HEATER will set to a temperature, NOT THE WATER! I learned this from another review. This means your water can get hotter and hotter and boil your fish without supervision!WHAT TO DO:I bought a simple $12 timed plug-in safety outlet that has options for 1 hour, 2 hours, 4 hours, or 8 hours. (Simple Touch C30004 the original Auto Shut-Off Safety Outlet, Multi Setting)You also must buy a thermometer! I bought this little one for $2.50 (Marina Floating Thermometer with Suction Cup).The thermometer has an easy to read green range from 70-80 degrees F, which is safe for most fish. Betas like it closer to 80 degrees. My average room temperature is usually around 72 degrees, and the 4-hour setting on my timed outlet always brings the temperature right up to 80 when I see that it's dropped to around 70. I would NEVER recommend using the 8-hour setting on the outlet, but the 4-hour setting is usually perfect to raise the temperature about 10 degrees, and the 2-hour setting will raise the temperature about 5 degrees. (Adjust depending on your own average room temperature)Together, all three of these things have kept my beta happy, warm, and healthy! The only downside (besides the heater requiring a timed-outlet) would be that I think my beta lost some of his tail due to frequent resting above the heater. He's just fine, but his tail looks kind of torn and I thought it may have been due to the heater.Good luck!

I bought this heater for my 3 gallon Betta aquarium tank. It's the middle of winter, and we keep our house heated to 71 degrees, and this heater heats our tank to almost 80 degrees. The directions say it's for 1/2 to 1 1/2 gallon aquariums, but I can't imagine using it in a tank that small unless the tank is in a really cold room, or you turn off the heater for part of the day. I actually had to turn the heater off tonight in my 3 gallon tank because my son noticed the water temperature was going above 80 degrees. If you buy this heater, it is a MUST to buy a thermometer with it to make sure it's not overheating your aquarium. (I bought the Marina Aquarium Thermometer, $5 on Amazon, great thermometer.) The suction cup on the heater doesn't really stick well, which is a minor issue, but still kind of annoying. Bottom line, if using this in anything under a 3 gallon tank, make sure to turn off every few hours so water doesn't get too hot. Even 3 gallon tanks probably shouldn't run this heater all day/all night without a break. Overall, great purchase and does the job!UPDATE: I've had this heater for 3 months now, and since it's an "always on" heater, I have to unplug it for a few hours every day and also in the evening or else it will overheat my 3 gallon tank. We are going away on vacation, and I didn't want to worry about leaving it on 24 hrs and it frying my beta with temps that are too high. So, I decided to replace it with a heater that is not "always on" and instead stays at a set temperature. I bought the Hydor 25Watt Aquarium Heater ($20 on Amazon), and have it set to heat my tank at a constant 79 degrees. No more plugging and unplugging the heater in as I've had to do with the Marina heater. Also, no need for timers and all the other stuff people are doing with this Marina heater to get it to not overheat their tank. If I were to do it again, would have started with the set- temperature Hydor heater to begin with.