I bought an AquaTop Nano 15w heater for my 2.5 gallon tank.

The above shows that manufacturers recommend 2~5 watts for each gallon of water. One thing I have noticed though, is that lack of wattage can be compensated by good water current in the fish tank to a certain point. Once after I had replaced my with a in my 40 gallon aquarium (because the Jager was too bright for my aquarium’s black background), the water temperature was stable because of the good water flow. The only difference is that the 50W heater has to stay on for a longer period of time than the 100w.

Does anyone know of or have a suggestion as to where I may find a decent heater for a small 2.5 gallon aquarium?

I just purchased a Neptune submersible aquarium heater 50 Watt which is recommended for a ten gallon tank. The 25 watt was recommended for a 5 gallon but i decided to go with the 50 watt. I was about to buy a new 10 gallon to put my betta in but i have no space left in my room for another tank. My question is would it be ok to use the 50 watt heater in a 2.5 gallon tank? or should i just try clear room out for a 10 gallon?

Fish Tank Heaters & Aquarium Thermometers | PetSmart

you recommend what type of heater would be best for a 2.5 gallon aquarium? The general rule for heating is 5 watts per gallon. So in a 20 gallon aquarium, you'll need at least a 100 watt heater. In a 30 gallon aquarium, you'll need at least a 150 watt heater.


I recently purchased a beta falls aquarium. I believe the tank is around 4 gallons. However, I had a hell of a time finding a 25 watt heater with a programmable temperature gauge, that was small enough to fit in the reservoir, and available at my local pet stores. I purchased a 50 watt heater (glass encasing) that is adjustable and it fits great (it’s impossible for the fish to come in contact with it, so not an issue). I set the heater at 78 degrees for my betas, I want to be sure it’s not going to overheat the water. Even though it has more watts than needed, it will still shut off at the desired temp correct?

Grreat Choice® Mini Aquarium Heater

I am at NJ and none of my shrimp tanks have heater including a 2.5gallon and 1gallon. Room temperature stays above 63F. well the water ends up staying around 70, but is that acceptable for the shrimp? seems a little chilly and on those little aquarium thermometers its just below that little green area.On the market, there are 7.5w, 10w, 15w, 25w aquarium heaters- all indicating that they will work just fine for a tank 5 gallons and under. BEWARE! Not all low wattage heaters are the same!Pet store bettas are, unfortunately, usually sick when you get them. The best thing to do is read up on them before buying and see if you can find one that's relatively healthy. You can also ask someone at the pet store when they normally get more bettas and try to get one from a new shipment.

If you're using melafix, use half or less of the recommended dose. There is another product by the same company called "bettafix", which is essentially the same but diluted. Melafix is actually pretty toxic, and bettas are affected by it more than most fish.

I always treated fin rot with just clean water and aquarium salt - about 1 teaspoon per 2.5 gallons of water. I'd put them in a smaller tank (my 2.5 gallon one instead of my 10 gallon one, usually) and change the water every day.For Chris, DSTOP, and Joseph, I have a relatively new 75 gallon aquarium and an older eheim heater. Don’t know what the wattage is, but it seemed to be staying on a lot and when I checked the temperature, the dial had moved up to 82 degrees–and I didn’t change it, so I don’t know what’s causing the slide upward. I want to replace the heater, and read that it can be a good idea to get two smaller heaters. Would that mean that I could get two Eheim heaters of 150 watts each instead of one at 300?