Are you looking for the heater for fish tank 20 gallon? Do you know what to consider before buying one? Well, we’ve managed to put together a list of the best heater for fish tank 20 gallon for your consideration. You can choose one and use it according to your needs.

In most cases, customers lack knowledge about market conditions, which leads to poor purchasing decisions. Fortunately, you have come to the right place as we will present you with a complete guide on how to select the heater for fish tank 20 gallon for you. We have searched for hours and spent a lot of time and effort making sure you get a good return on your hard-earned money.

You can find a quick comparison and a list of the top heater for fish tank 20 gallon below if you’re short on time.

Our Premium Picks!

EDITOR’S CHOICE
9.8
Orlushy Submersible Aquarium Heater,100W Adjustable Fish Tahk Heater with 2 Suction Cups Free Thermometer Suitable for Marine Saltwater and Freshwater

Orlushy Submersible Aquarium Heater,100W Adjustable Fish Tahk Heater with 2 Suction Cups Free Thermometer Suitable for Marine Saltwater and Freshwater

PREMIUM PICK
9.6
Tetra 26446 HT Submersible Aquarium Heater With Electronic Thermostat, 100-Watt,Multicolor

Tetra 26446 HT Submersible Aquarium Heater With Electronic Thermostat, 100-Watt,Multicolor

PREMIUM CHOICE
9.3
HITOP 25W 50W 100W 200W 300W Adjustable Aquarium Heater, Submersible Fish Tank Heater Thermostat with Suction Cups (100W-grey)

HITOP 25W 50W 100W 200W 300W Adjustable Aquarium Heater, Submersible Fish Tank Heater Thermostat with Suction Cups (100W-grey)

Best heater for fish tank 20 gallon

Orlushy Submersible Aquarium Heater,100W Adjustable Fish Tahk Heater with 2 Suction Cups Free Thermometer Suitable for Marine Saltwater and Freshwater

EDITOR’S CHOICE

Specifications:

Orlushy Submersible Aquarium Heater,100W Adjustable Fish Tahk Heater with 2 Suction Cups Free Thermometer Suitable for Marine Saltwater and Freshwater

$21.99
$18.99
 in stock
2 used from $15.89
Free shipping
Amazon.com
as of August 14, 2022 9:04 am

Features

  • ★100W aquarium heater is suitable for 10 to 20 gallons aquariums,Length - 9",voltage 110-120V, power cord is 6ft, please choose the right wattage aquarium heater according to our size chart.
  • ★It shows an area to adjust the temperature. It's not exactly accurate but it turns easy and can be adjusted at small intervals
  • ★Explosion Proof: 2mm thickened quartz glass,can be used in fresh water and salt water aquariums,easy to hide in the tank.
  • ★Precise temperature dial from 68 to 89°F allows for complete control of aquatic climate within a 1-degree difference.
  • ★Adjustable Aquarium Fish Tank Water Heater Sensitive and reliable thermostat maintains uniform temperature. Automatic shut off when the temperature is reached

Tetra 26446 HT Submersible Aquarium Heater With Electronic Thermostat, 100-Watt,Multicolor

PREMIUM PICK

Specifications:

Tetra 26446 HT Submersible Aquarium Heater With Electronic Thermostat, 100-Watt,Multicolor

$10.99  in stock
18 new from $10.98
4 used from $9.41
Free shipping
Amazon.com
as of August 14, 2022 9:04 am

Features

  • All Tetra HT heaters have indicator lights to let you know when the heater is on. It will be red when heating and green when the proper temperature has been reached.
  • The HT20 uses a built in electronic theromstat to automatically maintain water at 78° F which is ideal for most tropical fish. No adjustment is requried.
  • Ideal for aquariums between 10 to 30 gallons with hoods or glass canopies
  • The HT heater is fully submersbile and can be installed vertically or horizontally. It's small footprint makes it easy to conceal behind plants or other décor.
  • Please read all label information upon delivery. DO NOT plug heater into an electrical outlet until it is placed inside the aquarium.

HITOP 25W 50W 100W 200W 300W Adjustable Aquarium Heater, Submersible Fish Tank Heater Thermostat with Suction Cups (100W-grey)

PREMIUM CHOICE

Specifications:

HITOP 25W 50W 100W 200W 300W Adjustable Aquarium Heater, Submersible Fish Tank Heater Thermostat with Suction Cups (100W-grey)

$15.97  in stock
Amazon.com
as of August 14, 2022 9:04 am

Features

  • 100W aquarium heater, length 8.8-inch, power cord 4.9ft, designed for small fish tanks, recommended for aquariums 15 to 30 Gallons.
  • Adjustable and easy to use: This aquarium heater, adjustable temperature range 68 ~ 93 °F, after setting the temp you want, will on or shut off automatically when the water temperature changes, no extra adjustment is required.
  • Accurate Temperature Control: This fish tank heater built-in thermostat, will automatically keep the water at the set temperature within±2°F error. Comes with an sticker thermometer to detect water temp at any time.
  • Thickened Glass: 2mm thickened quartz glass, 33% thicker than 1.5mm normal aquarium heaters, much safer for human and your lovely fishes.
  • Easier installation, you can install it with any angle by 2 powerful suction cups, just make sure it is under water fully. Besides, we provide 1 more extra suction cup for spare (total 3 PCS), and we provide 12 months warranty.

Aqueon Preset Aquarium Fish Tank Heater 100 Watts

Specifications:

Aqueon Preset Aquarium Fish Tank Heater 100 Watts

$14.99  in stock
16 new from $10.00
4 used from $13.22
Free shipping
Amazon.com
as of August 14, 2022 9:04 am

Features

  • Preset to 78°, accurate to +/- 1°
  • No adjustment required
  • Shatter resistant
  • Fully submersible, auto shut-off when overheats, resets when cools down
  • LED light turns on when aquarium water is being heated

Uniclife 100 Watt Aquarium Heater with Thermometer, Fish Tanks Heater for 10-25 Gallon

Specifications:

Uniclife 100 Watt Aquarium Heater with Thermometer, Fish Tanks Heater for 10-25 Gallon

$12.99  in stock
Amazon.com
as of August 14, 2022 9:04 am

Features

  • Detect Temp Timely: With a built-in thermostat, it will automatically keep the water at the set temperature. The extra thermometer sticker allows you to detect water temp at any time.
  • Adjustable: Controllable temperature range from 68 °F to 93 °F (20-34 °C). Simply rotate the knob to freely regulate the temperature with deviations from ± 2 °F to ± 4 °F.
  • Heating Protection: Its indicator light turns red during working and automatically shuts off to stop heating when reaching the set temperature. No danger of overheating to your aquatics.
  • For 10-25 Gal Tanks: Measure 9.8 inches in length. Applicable for aquaculture and fresh, marine and tropical aquariums. Save your fish or plants from coldness to keep them vigorous.
  • Reliable Material: The 2 mm extra thick shatterproof quartz glass can prevent electricity leakage. And the iron-chromium heating wires feature fast heating to warm your tank fitly.

HITOP Mini Aquarium Heater 50W 100W, Adjustable Fish Tank Heater with Digital Temperature Display and External Setting Button, Shatterproof Heater for Saltwater and Fresh Water up to 30gallon

Specifications:

HITOP Mini Aquarium Heater 50W 100W, Adjustable Fish Tank Heater with Digital Temperature Display and External Setting Button, Shatterproof Heater for Saltwater and Fresh Water up to 30gallon

$21.97  in stock
Amazon.com
as of August 14, 2022 9:04 am

Features

  • HITOP Mini design small fish tank heater 100W, size: 4.5*3*1.2in, with 3 powerful suction cups and 1 temperature sticker, suitable for 10-30gallon betta fish tanks, turtle tanks, etc.
  • The External temperature adjustment button is convenient to adjust the temperature, and the adjustment range is 69-95°F. After the temp-setting is completed, the aquarium heater will heat the water to the set-temp, and then automatically stop heating, no need to more operations.
  • Digital temperature display, can display real-time water temperature and set-temp, built-in multiple temperature sensors, temperature detection is accurate, no additional thermometer is needed. When the adjustment button is pressed, the temperature flashes to display the set-temp.
  • With double safety protection, this fish tank heater has its own water level sensor device, if it out of the water, it will automatically stop heating. When the actual water temperature is higher than 94°F, the heater will automatically activate the over-heating protection and stop heating.
  • The design of thickened plastic protective cover is anti-impact and anti-corrosion, suitable for fresh water and sea water. The small heat dissipation holes on the cover of this fish heater can prevent fish from getting stuck.

Uniclife 50 W Aquarium Adjustable Heater with External Temperature Controller Submersible Heater with LED Indicator Light for 5-20 Gallon Fish Tank

Specifications:

Uniclife 50 W Aquarium Adjustable Heater with External Temperature Controller Submersible Heater with LED Indicator Light for 5-20 Gallon Fish Tank

$17.99
$15.99
 in stock
Amazon.com
as of August 14, 2022 9:04 am

Features

  • For 5 - 20 Gallon Tank: Measure 6.3'' L x 1'' D. Applicable for aquaculture and fresh, marine and tropical aquariums, providing the best living environment for your fish.
  • Adjustable Temperature: Come with an external controller ranging from 65 °F to 89 °F, allowing for precise temperature control without wetting your hands.
  • Automatic Shut-off: Its LED indicator turns red during work and automatically shuts off when it reaches your desired temperature. An essential reminder for heating.
  • Watertight Design: Made of 2 mm shatterproof, heat-resistant and extra thick quartz glass to prevent electricity leakage and scratching, ensuring the security of your fish.
  • Easy to Install & Use: Fully submerge the heater and fix it tightly to the tank vertically or horizontally with 2 strong suction cups. Ready for use after being powered on.

Orlushy 100W Submersible Aquarium Heater, Fish Tank Heater with Adjustable Temperature and 2 Suction Cups for 10-20 Gallon Tank 6ft Power Cord

Specifications:

Orlushy 100W Submersible Aquarium Heater, Fish Tank Heater with Adjustable Temperature and 2 Suction Cups for 10-20 Gallon Tank 6ft Power Cord

$18.98  in stock
Amazon.com
as of August 14, 2022 9:04 am

Features

  • 【100 Watt Aquarium Heater】: 100w aquarium heater is for 10-20 gallons fish tank, voltage 120V/60Hz, power cord 6(ft), heating rob length-9.5 inches.The temperature can be set to the values ranging from 68 to 93°F, please choose the right wattage aquarium heater according to our size chart
  • 【Updated Design】: The aquarium heater is made of quartz glass, featuring corrosion-proof and explosion-proof. It adopts brand new structural design and helps increase dispersing heat area and shorten the length of the heating rob, thereby raising heating efficiency by 20%
  • 【Intelligent Safety Protection】: When the indicator lamp is on, the heater starts to heat up the water. With automatic shut-off function and the thermostat inside, the heater maintains the tank water in stable and constant temp, automatically stop or start heating to keep the temp stability
  • 【Wide Range of Application】: The heater is suitable for use in marine water or fresh water. With 2 strong suction cups, the heater can be installed horizontally or vertically to the tank side and held in place well for aquariums, fish tanks, aquacultures and hydroponic systems
  • 【Tips】: 1.Please disconnect the power supply, remove the heater out the water after cooling it down for 10 minutes before cleaning the aquarium or changing the water 2.Please ensure the heater is fully submerged in water

Petbank 100W Aquarium Heater, with Temperature Remote Control and LED Temperature Display, Submersible Aquarium Heater with Thermometer Strip & Use Time Display Suitable for 10-20 Gallon Fish Tank

Specifications:

Petbank 100W Aquarium Heater, with Temperature Remote Control and LED Temperature Display, Submersible Aquarium Heater with Thermometer Strip & Use Time Display Suitable for 10-20 Gallon Fish Tank

$16.99
$10.99
 in stock
3 new from $10.99
2 used from $19.54
Free shipping
Amazon.com
as of August 14, 2022 9:04 am

Features

  • 【Intelligent Temperature Control】The intelligent IC chip adjusts the temperature, the temperature accuracy is within ±2°F (±1°C), and it is automatically heated to the set temperature. It is suitable for ultra-low water level heating. It is specially designed for tortoise tanks and fish tanks.
  • 【LED Digital Display & Temperature Remote Control】Cycle temperature adjustment 64-91℉; LED digital display and matching thermometer can observe the water temperature in real time; the temperature remote control allows you to avoid wet hands when adjusting the temperature.
  • 【Safety & Explosion-Proof】The aquarium heater automatically cuts off power when leaving the water. It uses an explosion-proof quartz tube and is equipped with a plastic anti-collision sheath to prevent your aquatic organisms from being injured by touching the heating rod.
  • 【Show Usage Time】Real-time monitoring of the life of the heating rod, which is convenient for you to replace the heating rod in time to ensure the continuous water temperature. The heating rod can be used continuously for up to 10,000 hours.
  • 【Note】It is forbidden to expose the main part of the aquarium heater to the surface of the water during use, and 100% diving use must be guaranteed, otherwise the LED display will display an "Er" abnormal code.. Please unplug the power when cleaning the fish tank or changing the water in the aquarium.

FREESEA 25 Watt Aquarium Betta Fish Tank Heater with Aquarium Submersible Thermometer

Specifications:

FREESEA 25 Watt Aquarium Betta Fish Tank Heater with Aquarium Submersible Thermometer

$15.99  in stock
Amazon.com
as of August 14, 2022 9:04 am

Features

  • ★【25 Watt Heater】: This Aquarium heater is suitable for 1 to 5 gallons aquariums, Length - 6.8 inch,voltage 110-120V, power cord is 4.0 ft, please choose the right wattage aquarium heater according to our size chart.
  • ★【Temperature range】: 63°F~95°F , It is very easy to adjust the temperature you need, we also deliberately give each customer a free diving thermometer, you can observe the water temperature of the fish tank at any time.
  • ★【Intelligent temperature control】: Automatic constant temperature function, when water temperature reaches to specified temperature value, heater will automatically stop heating, when water temperature is lower than the set temperature, heater will automatically start heating. Furthermore, Automatic safety shut-off feature, and overheating protection.
  • ★【Note】: 1. Aquarium heater is 100% submersible use only, during its heating time, heater must be 100% submerged into the water.,Please unplug the power supply when cleaning the fish tank or aquarium water changes. 2. Heater rod is suitable for people over 16 years of age. Children or minors should be under adult guidance or supervision.
  • ★【SATISFACTION GUARANTEED】: Gain the confidence to go hard with us! Our Aquarium Heater is built with durability in mind and safety for every design, In the remote possibility that you’re not satisfied with our product, just contact us, and we will gladly give you a new Aquarium Heater replacement. 12 Month Warranty and 24 Hour Professional After-sales Service.