If you have tropical fish you are going to need a way to heat the aquarium water for the fish to survive. You could try to find alternative ways to heat the water however you might run into trouble if the water gets too hot or cold. Fish will put up with small water temperature fluctuations however anything beyond that could potentially kill the fish. The best alternative to that happening is to have a reliable aquarium heater
The best heater for a small fish tank will be a reliable heater that can be set to a specific temperature and will keep the tanks water at that temperature. The heater should turn on when the water temp drops below the heaters set temperature and should then turn off promptly once the heater returns to water to the desired temp.
Small tanks have unique issues with finding heaters small enough but also powerful enough to ensure the water is kept at the temperature it should be, 24 hours a day 7 days a week. Smaller tanks are also prone to water temp fluctuations more often than a very large tank because of the relative size of the aquarium.
What is considered a small aquarium?
There is no worldwide aquarium hobby agreement on what size a small fish tank is. Personally from my own experience and for the purpose of this article I would say any tank that is 15 gallons or less is a small fish tank.
How many watts of heater per gallon of water?
If you want to error on the right side of the solution to this question I would recommend as close to 5 watts per gallon of water. You could go as low as 2 to 2.5 watts per gallon if you want.
I find though if you purchase a heater that is a bit on the low end for wattage for the size of your tank then the darn thing is on more than a heater really needs to be. So if you purchase a heater that is closer to 5 watts per gallon it won’t have to turn on as much to get the job done.
Best Heaters for Small Fish Tanks
All of the heaters I have listed below are not the only heaters available and there are probably hundreds to choose from. I have selected some options for the aquarium hobbyist that I feel are solid choices.
Best Heater for 3 Gallon or 13.6 Liter Tank [Betta tank maybe?]
The FREESEA 50 watt tank heater is the perfect option for a 3 gallon aquarium. FREESEA manufactures these heaters ranging from 50 to 300watts so you can heat aquariums from 1 to 50 gallons.
This excellent heater features:
- A large LED display so you can easily keep an eye on the temperature while the heater works.
- An inline temperature control switch that adjusts from outside the aquarium. This is very convenient to use.
- It’s small size and oval shape make it much nicer than the traditional tube style heaters.
- The 50 watt heater will heat anywhere from a 1 gallon to a 10 gallon tank. Although I would recommend this heater for no larger than a 5 gallon aquarium. The heater might have to work too hard to keep a 10 gallon at a constant temperature.
- I really like a heater that is completely submersible which this one is. You can hide this one if you have live plants or rocks to put in front of it.
- When you can purchase something that is a necessity like a heater and happens to be extremely affordable then that is a bonus. This heater is just that.
Check out this heater on Amazon FREESEA 50 watt aquarium heater.
Best Heater for a 5 Gallon (22.73 liter) Aquarium
The JUNBO Mini Heater is another submersible aquarium heater ideal for setups 5 gallons and less. This heater automatically regulates the waters temp and will turn on and off as required. Some good to know features include but not limited to:
- Auto heat regulation at approximately 77 degrees Fahrenheit. This might be a con for some depending on the fish in your tank however most species should be good at being kept in 77 degree water.
- Has a ceramic heating system and is anti-explosion and cracking which makes this heater a very safe choice for a 5 gallon tank.
- There is a 1 year quality guarantee on this unit. If you have any issues with this heating unit just contact the manufacturer.
To check out more information about this heater click here.
Best Heater for a 10 Gallon (45.46 liter) Aquarium
The Eheim Jager aquarium heater with thermostat is a traditionally looking heater made by a solid company in the aquarium supply industry. This specific model can be purchased in heaters ranging from 30 watts to 300 watts so you can find one for 99% of the aquariums you will see in people’s homes. What you will want for your 10 gallon aquarium is this 50 watt heater.
Some of the features ( but not limited too) of the Eheim aquarium heaters are;
- This is a fully submersible heater so you can hide it out of view.
- There is a safety feature that turns the heater off if the water gets too low in the aquarium.
- There is an on and off light indicator so you can easily see when the heater is heating or not.
- The glass it is made if is shock proof and is safe for freshwater and saltwater aquariums.
Best Heater for a 15 Gallon (68.19 liter) Aquarium
As recommended above for the 10 gallon size the Eheim heaters are a great choice. You could opt for a 75 watt heater if you are running a 15 gallon aquarium. If you like the Eheim then check out this 75 watt Eheim Heater over on Amazon.
If you prefer something a bit different I really like the look of the Cobalt Aquatics Neo-Therm aquarium heater.
- It has a really cool LED display that shows you the temperature the heater is set to as well as the water temperature of the tank both simultaneously.
- It has a unique flat design and other than the LED lights most people probably won’t know what it is when they see it in your tank.
To check out the Cobalt Aquatics 75 watt aquarium heater click that link.
Mini Heater for Fish Bowl
If you have a fish bowl chances are the fish you keep in it will also require a heater. For years people who weren’t very knowledgeable about the different species of fish would try to keep tropical fish in a bowl with zero success. Tropical fish require a heater. I don’t know about you but I don’t recall seeing a heater in my fish bowl when I was a kid. My parents just didn’t know any better.
If you had a goldfish in the bowl it would be already, for a while anyways as goldfish are in fact cold water fish however a bowl is just not large enough.
Now everyone has easy access to information on the internet to places like this website and can quickly find out what they need for fish bowls or any other size of tank. After all that let me tell you that if you have a fish bowl and are keeping a Betta or some other smaller tropical fish in it you need to purchase a heater.
My recommendation for a fish bowl heater is the Marina 8 Watt submersible heater. That link or the picture ink will take you to Amazon so you can find more out about the product. It is good quality and very affordable.
Best Aquarium Heater Controller
What is an aquarium heater controller you ask?
A heater controller is used to prevent a heater from overheating and boiling your fish. Not a lot of aquarium owners have a heater controller which is unfortunate considering they are not really that expensive.
To set up, all you do is plug your aquarium heater into an aquarium heater controller and set the temp you want your water to be on the controller. You still have to set the aquarium heater to the desired temp as well. Then there is a sensor attached to the controller that will go into the tanks water. If the temperature starts to get to warm the controller will shut down the heater.
It is really easy to set up and can save the lives of your fish and you some money if you end up having a faulty heater.
The Inkbird Thermostat Temperature Controller is the heater controller I am recommending.
It has some really great functionality and is easy to use and get setup right away.
To read more about it I will leave a link here Inkbird Thermostat Controller.
Bonus Related Questions Answered for Best Heater for Small Fish Tank
Of course there are always so many questions to be answered in this hobby. I was able to identify some common questions being searched online and found this to be an excellent time to answer them.
How to Introduce a Heater to an Aquarium
If you have never placed a heater into an aquarium before what you need to know is to make sure the heater is either unplugged or turned off before you introduce it into the tank. Once there then you can plug it in. if the heater is a fully submersible heater make sure you submerse it fully before turning it on. Some heaters are made to have the top dial section sticking out of the water. Same rules apply for those types of heaters as well.
Best Position for an Aquarium Heater
The best aquarium heater placement differs from tank to tank. If you consider how the heated water will flow throughout your aquarium you should consider placing any heaters as low in the tank as possible. Heat in the water is no different than heated air so it rises which makes sense that placing the heater as low as possible will be the best location.
Also depending on where your filtration flows into the tank and is pulled out of the tank you might want to play around with placement. The idea is to get the heater in a location that will maximize its effectiveness.
- How to Heat a Fish Tank without a Heater
If you have tropical fish you really should have a heater for them. If for some reason you can’t afford one at the moment then there are ways to heat an aquarium without a heater. Although I don’t recommend it. Heat fluctuations can be dangerous to your fish. You won’t have control of the temperature unless the water is being heated by a heater that will turn off once it hits the desired temperature.
So whether you are looking to warm up a betta tank without heater or any other fish tank here are a few options.
- Setup the tank near a heat source like a forced air vent or even better would be near hot water heat. Some homes are heated via a boiler system so the heat distribution wouldn’t be as harsh as a forced air system blowing near the tank.
- Placing an aquarium near a large window but not in a way that the sun will shine directly on the tank is a good way to warm it up.
- Positioning your tank in the middle of your home where the temperature stays most stable is a great way to avoid temperature fluctuations.
- Using fluorescent type aquarium bulbs on the tank will help to warm up the water while the lights are on. The night time might pose a problem though when the lights are off.
So you can see there are other options to heating an aquarium however it would be very difficult to find an option that doesn’t cause drastic temperature fluctuations in the water.
So you can see the best solution is to have a heater for your small fish tank.
I recommend you also check out my recommended pages for heaters and filters for more options.
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