AqueonFish Tank Mini Heater, 10-watt, Plastic

I like this heater for my Biorb 4 gallon tank (for my betta) it keeps the tank 78 constant - so perfect - never had a problem, it's small and it works. It's made in Italy of all places. Just follow the directions. Don't turn it on until it's immersed in water. That's it. It works. My betta is perfectly warm and happy in his own Biorb tank. I know some of the reviews are not so great - but I followed the directions (immerse first, then turn on) and never had a problem, it works!!!P.S. I did have one day - heat wave here in CA where the ambient temp in the house was almost 90 and the tank was at the top of the safe zone - so I unplugged the heater that day and plugged it back in the morning. It was fine. I will have to see how it goes in the summer - but we will have the AC during those heat waves (hopefully). So I would caution if you do see your in house temps rising to keep eye on it - and in that case it's easy just unplug! It only went down a few degrees that night - still in the safe zone but I didn't want my betta to cook!

Have been using Aqueon preset heaters for years. Have never made a negative review before. Purchased it and discovered it’s not preset or able to be set . It depends on the filter flow and room temperature. Yes it’s possible to find the correct balance. But if something changed. It could do permanent damage to the fish. Very sorry. Will understand if you don’t wish to post it.

This heater is good. I replaced an older one that I've had, which worked quite well for 2 years or so. I had a fishy emergency and left the heater plugged in and put of the tank. This overheated the unit and caused it to fail. My mistake. Be sure not to do that.However, the one I killed always kept my 2.5 gal tank at a perfect 72 degrees.This is NOT a good product to use in a tank under 3 gallons. It gets far too hot, even with proper circulation.I will purchasing a larger tank to replace the 2.5 gal and I will be putting this heater back into that tank.Over all, this product works well. Maintain good water circulaton and probably ensure its at very least 3 gallons or more.

I know people say that if its out of water and you lug it it it will blow the internal fuse. Let me be the first to say it take time for it to heat up and blow it. Ive plug this thing in twice with my 10 gallon tank and walked away and came back 5 minutes later and noticed it plugged in...after i unplugged it and got it back in my tank when the water was in it, it still worked fine

I bought this little heater for my Aqueon Betta Falls that I purchased from a pet store. I soon found out that this is a very poor choice. Why? It has no thermostat, it simply heats the water. I have 2 thermometers on my Betta Falls, one below with the heater and one above in the center tank. They vary about .2 degrees Fahrenheit. This heater will heat the water according to the ambient temperature of your room. My room was 72 degrees Fahrenheit.....this heater heated my Betta falls to 88.9 degrees Fahrenheit. I turned my room thermostat down to 60 degrees Fahrenheit and the Betta Falls water temperature became 71.9 degrees Fahrenheit. I again turned my heater up to 70 degrees Fahrenheit the Betta Falls rose to 84.9 and continued to rise. Therefore, this is a bad choice for a Betta Falls. I then went to the pet store and purchased a 20 watt Heater designed with Bettas in mind. It is made by TOPFIN. It has a light that is green when not heating and orange when it is heating. I can see that very well. It has a thermostat with a preset temperature of 77 degrees Fahrenheit plus or minus 1.8 degrees Fahrenheit. It keeps my Betta Falls at 78.4 degrees Fahrenheit continuously with no perceptible deviation to my thermometers. This is acceptable in my book. This heater by Aqueon will cause your fish great stress possibly killing them and your plants.

I absolutely love these heaters! I purchased 5 of them! Each of my little ones are in bowls so they get cold and unsocial. But thanks to these heaters they are up and swimming around. My house is usually so cold I fear they will get sick. I usually turn them off the heaters when I leave the house and it takes a bit for them to warm up the bowl but beside that there isn't anything negative about this product.

I ordered two of these and they arrived on my doorstep in an unbelievable 38 hours. Works well right out of the box. I was pleasantly surprised to find that the cords are of a generous length, which made them easy to plug in without an extension cord. Lots of manufacturers skimp on the cords in order to keep the costs down. Not so with these units.So far I'm very pleased and so are my kids' two, previously miserably cold betta fish.

Pro: small, not glass, sticks well with the suction cups (comes with 2)Con: Maybe mine is defective? But my tank is actually TOO cold. Without a heater, the water is ~60-63F. With my old heater (7.5 watts - don't remember the maker) it was raised to ~65-68F. With this heater, it's only raised to 70F. I actually bought this heater hoping it would overheat because my tank is too cold (I have 1 betta in a 2.5 glass tank with a screen top). I'm wondering if the screen top is the reason? Nothing keeping the heat in? What other top/cover could I use?