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Best Betta Tank Heater For 1, 5 and 10+ Gallon Tanks

Next to selecting your aquarium, the most important part of setting up a betta tank is choosing your heater. Like most tropical fish, bettas require warm and consistent water temperatures to stay healthy and thrive. Choosing the best betta heater for your tank, whether it’s 5-gallon or bigger, is a critical part of the process.

Some aquarium kits come with a heater, but most of the time aquarists have to add one to their set-ups. With so many options, how do you pick the best type of heater for your betta fish tank?

Quick Comparisons of the 5 Best Betta Heaters

IMAGE BRAND DETAILS
tnk-table__imageEheim Jager TruTemp Aquarium Heater
  • Type of Heater: Submersible
  • Thermostat: Yes, integrated
  • Power: 50 to 300 Watt Versions
  • Ideal Tank Size: 75W(26-gallons)
View on ChewyView on MarineDepot
tnk-table__imageTetra HT10 50-Watt Submersible Heater
  • Type of Heater: Submersible
  • Thermostat: Integrated
  • Power: 50 Watts
  • Ideal Tank Size: 50W(10-gallons)
View Product
tnk-table__imageAqueon Preset Aquarium Heater, 50W
  • Type of Heater: Fully Submersible
  • Thermostat: Preset Integrated
  • Power: 50 to 200 Watt Versions
  • Ideal Tank Size: 50-200W(up to 20 gallons)
View Product
tnk-table__imageFluval Marina Submersible Mini Heater
  • Type of Heater: Submersible
  • Thermostat: Integrated
  • Power: 25 Watt
  • Ideal Tank Size: 25W(5.5-gallon tanks and bowls)
View Product
tnk-table__imageHygger Mini Submersible 50-Watt Heater
  • Type of Heater: Submersible
  • Thermostat: Integrated
  • Power: 50 Watts
  • Ideal Tank Size: 50W(up to 6-gallons)
View Product

Quick Guide to Betta Heaters

You need an aquarium heater for your betta set-up because they prefer warm aquarium water. The ideal range for bettas is about 75°F to 86°F. It’s unlikely that your tank will stay in this range naturally without using supplemental heat.

Bettas also do not do well if their water temperature fluctuates more than a degree or two. Frequent changes in temperature may cause your betta to feel stressed and get sick. The most common reason for a betta to lose color or stop eating is a tank that’s too cold or one that shifts temperature too much.

Monitoring Your Tank’s Temperature

Hygger Mini Submersible Aquarium Heater temperature control guide.

A good heater with a built-in thermostat will keep your tank at the set temperature automatically. You can monitor the temperature using a thermometer sticker on the glass side, or by using an in-tank thermometer. Your temperature may vary to within a few degrees depending on the placement of your thermometer and heater.

Do you still need a heater and temperature gauge for a betta fish bowl? Yes! If you can’t find a heater that will fit in your tank, chances are it’s too small for your fish. Upgrade to at least a 5-gallon set-up with a heater and thermometer, and your betta will probably be a lot happier.

Types of Aquarium Heaters

There’s actually a wide variety of heaters on the market for aquariums and terrariums. The majority of these styles are not suitable for small fish tanks or betta bowls. Briefly, the types of heaters you’ll find as you shop include:

Style of Heater

Immersible and Submersible Heaters

Sump Heater

Undergravel Heater

Under-Tank Heat Matt

How it Works

Sits partially or fully immersed in the aquarium. When the water temperature drops below the desired setting, the thermostat turns the heater on until the temperature is raised sufficiently

Fits inside the filtration system and heats the water as it flows into the tank or pond

Heating cable is sandwiched between layers of aquarium substrate and heat is concentrated in the lower part of the aquarium

Heating pad sits underneath the aquarium and heats the bottom of the tank

Best Heater For

Aquariums of all sizes

Large aquariums (100+ gallons) or ponds with extensive filtration systems.

Not a popular method in aquariums since the mid 1990s. Used primary in large aquariums (over 50-gallons) with emphasis on maintaining live plants rather than fish

Glass terrariums and reptile tanks

Style of Heater

Immersible and Submersible Heaters

How it Works

Sits partially or fully immersed in the aquarium. When the water temperature drops below the desired setting, the thermostat turns the heater on until the temperature is raised sufficiently

Best Heater For

Aquariums of all sizes

Style of Heater

Sump Heater

How it Works

Fits inside the filtration system and heats the water as it flows into the tank or pond

Best Heater For

Large aquariums (100+ gallons) or ponds with extensive filtration systems.

Style of Heater

Undergravel Heater

How it Works

Heating cable is sandwiched between layers of aquarium substrate and heat is concentrated in the lower part of the aquarium

Best Heater For

Not a popular method in aquariums since the mid 1990s. Used primary in large aquariums (over 50-gallons) with emphasis on maintaining live plants rather than fish

Style of Heater

Under-Tank Heat Matt

How it Works

Heating pad sits underneath the aquarium and heats the bottom of the tank

Best Heater For

Glass terrariums and reptile tanks

Choosing Between Immersible and Submersible Heaters

The best styles of heaters for tanks under 50-gallons and smaller fish bowls are the immersible and submersible types. Both styles usually have a glass tube containing a heating element and thermostat that goes inside your aquarium.

When the thermostat turns on, the element inside gets hot and heats the water around the glass tube. You adjust the thermometer setting via a dial or control knob.

The main difference between these styles is that an immersible heater is not completely waterproof. Instead, the control mechanism sits outside the water and the heater attaches to the top edge of your tank, similar to a HOB filter. Submersible heaters are totally waterproof and sit completely under the water in your aquarium.

Heater Adjustability

Immersible and submersible heaters can be set by moving their control dial or knob and selecting your desired temperature. Depending on the conditions in and around your tank, you may have to make further adjustments. In the summertime, for instance, I have to turn my aquarium heaters up a little to compensate for my A/C.

Immersible heaters can be easier to adjust because their control dials sit out of the aquarium water. In contrast, you may have to reach into your tank to adjust your submersible heater. But submersible heaters are usually higher quality and last longer. They’re typically more expensive too.

Pick The Right Wattage for Your Tank Size

Heaters are ranked by how much power they draw per hour, in watts. The right heater for your tank will depend on how much water it holds and how much you need to increase the water temperature. If your home is on the warmer side year-round, you can get by with a heater that draws less power and has a lower wattage.

If you need to raise your aquarium more than 10 degrees above room temperature, however, you’ll likely need a heater with more power. You can go with the next size up but will have to monitor your tank’s temperature during the warmer months. Otherwise, it could overheat your tank.

I don’t recommend using tanks under 5-gallons for bettas, and heaters under 25-watts are often unreliable. Here are some guidelines to follow when selecting a heater for your tank:

Aquarium Size (gallons)

Fish bowls and tanks
2.5 and under
(not recommended for bettas)

5

10

20 to 25

Raising Water ~10°F

5 to 7.5 Watts
May not be reliable

15 to 25 Watts

50 Watts

100 to 150 Watts

Raising Water More Than 10°F

7.5 to 10 Watts
May not be reliable

50 Watts

100 Watts

150-200 Watts

Aquarium Size (gallons)

Fish bowls and tanks
2.5 and under
(not recommended for bettas)

Raising Water ~10°F

5 to 7.5 Watts
May not be reliable

Raising Water More Than 10°F

7.5 to 10 Watts
May not be reliable

Aquarium Size (gallons)

5

Raising Water ~10°F

15 to 25 Watts

Raising Water More Than 10°F

50 Watts

Aquarium Size (gallons)

10

Raising Water ~10°F

50 Watts

Raising Water More Than 10°F

100 Watts

Aquarium Size (gallons)

20 to 25

Raising Water ~10°F

100 to 150 Watts

Raising Water More Than 10°F

150-200 Watts

Aquarium Heater Safety

Heaters can be a safety risk, so you should always use care when handling or using them. I nearly started a house fire when the water in a plastic container evaporated below the heater’s glass tube. The heater was plugged in, so when the thermostat turned it on the glass shattered and started melting the plastic container.

If you have to remove your heater from your tank, always unplug it and allow it to cool down first. Keep your heater anchored to your tank properly so it won’t shift around. The glass tube is fragile and can easily be broken or cracked if it smacks against the side of your tank or runs into your decor.

pull the plug concept with man pulling black cord and plug. Close up

If your heater’s glass tube breaks or shatters while inside your tank, immediately unplug the heater! Don’t reach inside the tank while the damaged heater is plugged in, or you could be electrocuted. This is a rare event. I’ve only had this problem once in 35 years of fish keeping. Heaters are usually safe if used as directed.

Top 5 Betta Heater Reviews

Let’s take a look at a selection of popular aquarium heaters and compare their ideal tank sizes and temperature ranges. While premium heaters may cost up to twice as much as the less-expensive versions, they are usually more reliable, durable, and long-lasting.

I have several high-quality submersible heaters in my collection that are more than 25-years old and still work perfectly. So you can think of a heater as a long-term investment. If you opt for a cheap heater, it may not be as reliable and you may have to replace it more frequently. For a small betta tank heater, this may not be a problem.

1.Eheim Jager TruTemp Aquarium Heater

Eheim Jager TruTemp Aquarium Heater
  • Type of Heater: Submersible
  • Thermostat: Yes, integrated
  • Power: 50 to 300 Watt Versions
  • Temperature Range: Adjustable from 64.4°F to 93.2°F
  • Size: 2.6 x 2.0 x 13.6 inches
  • Ideal Tank Size: 75W: 26-gallon
View on Chewy View on MarineDepot

German manufacturer Eheim makes a range of high-quality aquarium equipment, including filters and heaters. The TruTemp aquarium heater measures 1.4” x 19.9” and is designed to be fitted vertically in your tank.

Whatever size of a tank you have, there’s a TruTemp model to suit your needs. This heater comes in different watts, ranging from 50 watts right through to 300 watts, and there are nine sizes available.

If you’re looking for a heater for your betta tank or nano aquarium, the 25-watt unit is your best choice, as that can heat the water up to 78° F in tanks up to 7-gallons capacity.

The heater is made from shatterproof glass, and it’s shock-resistant for safety. Also, in the event that your water level falls too low, the heater has a handy auto-shutoff feature.

Pros

  • Indicator light shows when the unit is operational
  • Shatterproof and shock-resistant
  • Automatic shutoff feature when the water level falls too low
  • 0.5-degree calibration tolerance
  • Three-year warranty

Cons

  • Heater unit is very long and might be awkward to fit horizontally

2. Tetra HT10 50-Watt Submersible Heater

Tetra HT Submersible Aquarium Heater With Electronic Thermostat
  • Type of Heater: Submersible
  • Thermostat: Integrated
  • Power: 50 Watts
  • Temperature Range: 78°F
  • Size: 5.2 x 1.6 x 3.5 inches
  • Ideal Tank Size: 10-gallon
Check The Price

If you’re looking for a bargain, then you probably can’t find a better option than the Tetra HT 50-watt submersible heater with an integrated electronic thermostat. This little heater has a durable cap to protect the glass tube from damage. It’s the ideal size for a 10-gallon betta aquarium.

The Tetra keeps things simple, and I think that’s its most remarkable feature. Instead of having to fumble underwater to adjust the temperature, the Tetra’s thermostat automatically heats your tank to 78°F. The red light tells you when it’s heating, and the green light comes on when it stops.

If you need a lot of flexibility in a heater, this one might not be for you. But if you just need a reliable betta tank heater with a thermostat, this is an excellent option. I keep an older version of this heater on hand for emergencies, and it’s never let me down. It may not be as fully-featured as other heaters, but at the price it’s hard to beat!

Pros

  • Inexpensive submersible heater with a thermostat that should fit into most betta keeper’s budgets.
  • Red and green lights tell you when the heater is on and when your tank has reached the set temperature.
  • Integrated thermostat automatically heats your tank to 78°F, so you don’t have to adjust its settings.

Cons

  • Temperature is not adjustable, so if you prefer a temperature other than 78°F this heater won’t work.
  • May not work well for tanks located in colder areas, since the heat-level can’t be increased.
  • May be too powerful for smaller tanks and betta bowls.

3. Aqueon Preset Aquarium Heater, 50W

Aqueon Preset Aquarium Heater, 50W
  • Type of Heater: Fully Submersible
  • Thermostat: Preset to 78° F
  • Power: 50-200 Watts
  • Temperature Range: Fixed at 78° F
  • Size: 3.5 x 1.5 x 7 in inches
  • Ideal Tank Size: Up to 20 gallons
Check The Price

Aqueon makes high-quality aquarium equipment that’s popular with experienced hobbyists and beginners alike because of the quality and durability of their products. And, if you’re on a budget, the Aqueon preset heater is the ideal choice for you. 

The compact heater is preset to a temperature of 78° F, which is ideal for most tropical fish species, including bettas. The heater also comes in three higher wattage options, including 100 Watts, 150 Watts, and 200 Watts, so there’s a model to suit larger tanks too.

You can install the compact heater horizontally or vertically, and the glass is shatter-resistant for safety. An LED indicator shows you when the heater is actively heating your tank, and an automatic shut-off feature prevents overheating.

Pros

  • One-year warranty
  • No-hassle, preset design
  • LED indicator shows when the heater is active
  • Automatic overheating shut-off feature

Cons

  • Heat setting cannot be adjusted

4. Fluval Marina Submersible Mini Heater

Fluval Marina Submersible Heater for Aquarium, Mini
  • Type of Heater: Submersible
  • Thermostat: Integrated
  • Power: 25 Watt
  • Temperature Range: Varies
  • Size: Heater Rod 6-inches long
  • Ideal Tank Size: 5.5-gallon tanks and bowls
Check The Price

If you need a small betta tank heater, consider this mini option from Fluval. It’s the ideal size for small 5-gallon aquariums and straight-sided fish bowls. The Fluval isn’t fancy or full of features, but it’s a reliable little heater and incredibly inexpensive. It would make an excellent choice for a breeding or quarantine tank too.

The Fluval Marina is an old-school glass tube heater that’s been on the market for years. The integrated thermostat does the hard work of turning the heater on and off for you. You adjust the temperature by turning the control dial up or down. It couldn’t be simpler to use!

The Fluval may be a bit trickier to set than other designs because the dial is underwater, and the display doesn’t show a list of temperatures. You have to turn it on first and see how warm your aquarium gets, and then adjust the temp up or down from there. Still, this is an excellent option for small tanks or larger betta bowls.

Pros

  • Inexpensive, old-school design is a reliable classic.
  • Has an integrated thermostat and protective cap on the glass heating tube.
  • Small 6-inch long heating rod should fit inside most 5-gallon tanks and fish bowls.

Cons

  • Temperature dial is not marked, so you’ll have to allow the heater to come to temperature before you can adjust it up or down.
  • Temperature dial is underwater when in use, so you have to reach into the aquarium to adjust.
  • Limited use and flexibility, since its maximum tank size is 5.5-gallons.

5. Hygger Mini Submersible 50-Watt Heater

Hygger Mini Submersible Aquarium Heater 50W 100W Adjustable LED Digital Temperature Display Small Tank Heater for Turtle Betta Fish Water Heater with Protective Guard
  • Type of Heater: Submersible
  • Thermostat: Integrated
  • Power: 50 Watts
  • Temperature Range: 63°F to 94°F
  • Size: 2.7 x 1.4 x 4.5 inches
  • Ideal Tank Size: up to 6-gallon
Check The Price

What do you do if your tank is curved so you can’t attach anything to its side, or if you need a heater for a betta fish bowl? One option is this fascinating little mini heater from Hygger. Instead of using a long glass heating rod, this heater is flat and encased in a thermoplastic housing.

The Hygger Mini sits on the bottom of your tank or hangs in a discrete corner if you prefer. It’s nearly indestructible design is durable and protects your fish from harm. The external control panel makes it easy to adjust without having to get your hands wet, too!

The Mini’s heating unit has an LED display that shows the current water temperature and has a light to indicate when the heater is turned on. The integrated thermostat takes care of the hard work, so you can sit back and enjoy watching your betta play. This is an ideal option for awkwardly-shaped tanks and bowls under 6-gallons in size.

Pros

  • Shatterproof flat housing renders heater nearly indestructible.
  • External control panel and 1-touch button make it very easy to set and adjust.
  • Does not need to be anchored to the side of a tank, so ideal for curved tanks and betta bowls.

Cons

  • Pricier than the other options for small tanks and betta bowls.
  • May be too powerful and overheat tanks under 5-gallons in size.
  • To lower the temperature setting, you have to reset the control panel and adjust the temperature upward to your desired number.

Conclusion

Hygger Mini Submersible Aquarium Heater inside aquarium.

There’s a lot of options when you’re looking at heaters for your betta fish. While you can always opt for an aquarium kit (buy a betta fish tank with heater), adding a heater is not usually an expensive proposition. It’s definitely worth it to invest in a betta tank heater with a thermostat if you have that option in your price range.

The good news is that most designs these days include a thermostat, even in budget or economy heaters. Choosing between aquarium heaters will likely come down to your price range and the list of features you need for your tank. Even heaters for betta fish bowls come with premium features these days!

Hopefully, you’ve found a couple of options suitable for your tank on my list, and we’d love to hear which heater you choose in the comments! If you still need some help deciding, consider these factors:

  • If you’re looking for a premium heater that’s shatterproof and comes in a wide variety of sizes, my Best High End pick, the Eheim Jager TruTemp Aquarium Heater, is an excellent choice.
  • For aquariums larger than 30-gallons, look at the Best Option for Larger Tanks.
  • If you need a heater for a small tank or betta bowl, consider:
    • Fluval Marina for 5-gallon tanks.
    • Hygger Mini for bowls and tanks 6-gallon and under.
  • For fish keepers on a tight budget, the Tetra HT gets the job done and is a long-lasting and reliable workhorse.

Jen has more than 30 years experience as a biologist, aquarist, and fishkeeper. She is an expert in setting up new tanks and maintaining naturally-planted freshwater habitats, and has experience raising a wide variety of aquatic species.

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