Many of the freshwater and saltwater fish we keep are bred and not wild-caught, but they retain their native environmental needs. Many of these fish are tropical fish, which means in most home environments they will need an aquarium heater to keep the water temperature at a level that keeps them happy and healthy.
If you keep bettas, tetras, guppies, and even dwarf shrimp, they require a stable, warm water temperature.
If you’ve looked for an aquarium heater in your local fish store or online, you’ve probably been overwhelmed by the options. There are different sizes and shapes, different levels of adjustment, and even options for smart heaters.
Finding the right heater for your aquarium can be overwhelming, so here are reviews of the 10 best aquarium heaters to help you pick the best product to meet your aquarium’s needs.
A Quick Comparison of Our Favorites
|Best Overall||Aquatop Submersible Glass Aquarium Heater||
|Best Value||Tetra HT10 Submersible Aquarium Heater||
|Premium Choice||Cobalt Aquatics Electronic Aquarium Heater||
|Eheim Jager Thermostat Aquarium Heater||
|Marina Betta Submersible Aquarium Heater||
The 10 Best Aquarium Heaters- Reviews 2021
1. Aquatop Submersible Glass Aquarium Heater – Best Overall
The Aquatop Submersible Glass Aquarium Heater takes the spot as the best overall aquarium heater for its simple but functional design and fair price. This aquarium heater is available in 7 sizes from 50-300 watts.
This heater is made from double insulated glass and is fully submersible. The insulation around the heating element will help protect your fish and invertebrates from injury if they touch the heater while it is running. For temperature control, all you have to do is turn the red knob on top of the unit. This heater can be adjusted from 68-93°F and has an indicator light below the temperature gauge that lets you know when the heater is actively working to heat the water. Suction cups are included to attach the heater to the interior of the tank.
Even though this unit is fully submersible, the manufacturer recommends installing it with the temperature adjustment knob above the waterline. This heater can only be mounted vertically or angled but should not be mounted fully horizontally or on the bottom of the tank.
2. Tetra HT10 Submersible Aquarium Heater – Best Value
The Tetra HT10 Submersible Aquarium Heater is the best aquarium heater for the money because it is functional but affordable. This heater is 50-watts and is not adjustable.
This heater maintains the water temperature at a preset 78°F, plus or minus 2°F. It features an indicator light that shows up red when the heater is actively running and shows up green when the heater is on standby. This heater can be installed vertically or horizontally and is fully submersible. This heater only measures 8.25 inches tall, so it’s easy to hide behind plants, bubble walls, or aquarium décor. It is intended for tanks from 2-10 gallons.
The suction cup included with this heater does not clip on and off, but instead it completely circles the heater. This means it’s more secure from being knocked loose but also more difficult to clean and maintenance. Since you cannot adjust the temperature of this heater, if it isn’t calibrated properly then you will need to closely monitor the water temperature.
3. Cobalt Aquatics Electronic Aquarium Heater – Premium Choice
The premium choice for aquarium heaters is the Cobalt Aquatics Electronic Aquarium Heater because it’s functional and has a sleek design but also has a premium price. This heater is available in 5 sizes from 25-150 watts.
This heater is fully submersible and is thin and flat, making it a good fit for tanks and even terrariums and vivariums. It can be set between 66-96°F and is accurate within a plus or minus 0.5°F range. It features an LED display that shows both the current tank temperature and the set temperature. It also features one-touch setup and temperature adjustment. It’s inside of a shatterproof casing that the manufacturer considers to be nearly indestructible. It has a built-in thermal protection circuit that provides an automatic heater shutdown to prevent overheating. This heater can be installed horizontally or vertically.
For proper functionality, the adjustment dial and the lower portion of the heater must be submerged. Depending on tank size and setup, this heater may not thoroughly heat the entire tank.
4. Eheim Jager Thermostat Aquarium Heater
The Eheim Jager Thermostat Aquarium Heater is an effective glass aquarium heater. It is available in 7 sizes from 50-300 watts. This aquarium heater is made from specially made glass to protect against the heating element inside and to increase the efficacy of the heater. It can be adjusted from 65-93°F with a control knob that is easy to use. This heater is built to keep your aquarium at the temperature you set it to, and it can easily be recalibrated if it is not heating to the correct temperature. It can be fully submersed and can installed horizontally or vertically. It includes clip-on suction cups to mount the heater inside of your tank.
It’s best to use this heater in conjunction with a separate thermostat that can be used to monitor the tank temperature to ensure the temperature is staying in range. It also may be necessary to use a bucket full of water to calibrate this heater to ensure that it is calibrated correctly before using in your tank.
5. Marina Betta Submersible Aquarium Heater
The Marina Betta Submersible Aquarium Heater is a great heater pick for tanks and bowls 1.5 gallons and smaller. This 8-watt heater is not adjustable and is only available in one size.
This heater is small, flat, and fully submersible, so it can be installed vertically or horizontally via the attached suction cup. It is made to keep the tank temperature around 78°F, plus or minus 2°F. This heater is enclosed in polymer that is shatterproof and extremely difficult to break. It features a red indicator light to show you when it is actively heating.
This heater does have to be fully submerged to work correctly. It’s important to monitor the water temperature with a thermostat to ensure the heater is working correctly and keeping the water at a safe temperature.
6. Fluval Submersible Glass Aquarium Heater
The Fluval Submersible Glass Aquarium Heater is a 50-watt heater made with a unique reflective coating that helps it blend into your aquarium. It measures almost 15 inches long but less than 2 inches in diameter.
This heater has a temperature adjustment knob that allows for a temperature range from 68-86˚F. The ceramic heating element is encased in impact-resistant glass. This heater features a blue indicator light to let you know when it’s actively heating the tank. It includes two clip-on suction cups to mount it to the tank. The clips on the suction cups are silver, making them blend into the color of the heater and making them almost invisible. It can be installed horizontally or vertically.
This heater should be almost completely submerged at all times to allow for proper function. If water is not able to circulate around the heater, then it will not work correctly and may cause damage to the heater or your tank. This heater can be plus or minus 3˚F of the set temperature, so it should be closely monitored, especially upon initial setup. This product is more expensive than some other similar products.
7. Orlushy Submersible Aquarium Heater
The Orlushy Submersible Aquarium Heater is available in 5 sizes from 100-500 watts, making it the highest wattage heater on the list. This heater includes a free digital aquarium thermometer.
This heater features fire-retardant padding and a rubber “crash pad” to prevent damage if it drops within the tank. It has a temperature adjustment knob that is easy to grip and use. This heater can be set from 68-89˚F and is accurate within plus or minus 1˚F. It features a red indicator light to let you know when it’s heating the water. This heater is fully submersible and can be installed horizontally or vertically.
This heater should be almost fully submerged at all times for proper functioning. The clip-on suction cups included with this heater must be seated toward the upper part of the heater or they will be warped and damaged by the heat. The sensitivity of this heater can be too high, causing it to over or underheat with minor adjustments.
8. FREESEA Aquarium Heater
The FREESEA Aquarium Heater is a compact heater intended for tanks 20 gallons and below. It is available in 3 sizes from 50-100 watts.
This heater features a LED display that shows the actual temperature within the tank at a given time. This heater can be adjusted with a single button from 59-94˚F. This heater is completely submersible and will not function correctly if it is not always submerged. This heater is compact and designed to be installed vertically or horizontally in nano and small tank setups. The heating element is seated inside of a durable plastic case.
This heater’s temperature adjustment is done from a controller located on the electrical cord, but this controller is not waterproof and may be broken if dropped into the water. The LED display on the heater is on all the time, which makes it difficult to hide this heater within the tank.
9. Mylivell Aquarium Heater
The Mylivell Aquarium Heater is a glass-encased heater that is available in 4 sizes from 50-300 watts. The manufacturer recommends the smallest size for tanks from 10-20 gallons, so this may not be the best option for smaller tanks.
This heater must be almost fully submerged at all times to function, but it can only be installed vertically. This heater features a temperature adjustment knob and can be adjusted from 65-93˚F. It has a red indicator light to let you know when it’s actively heating and includes two clip-on suction cups for mounting. It also has a black rubber bumper on the bottom to prevent damage if the heater is dropped in the tank.
This heater is not made from shatterproof glass, so it may be broken by drops or rough handling. It also may shatter if it glitches and overheats. This heater does not always heat to the appropriate temperature, so it’s important to monitor the temperature with a thermometer.
10. Aqueon Preset Aquarium Heater
The Aqueon Preset Aquarium Heater is available in 4 sizes from 50-200 watts. The heating element is encased in shatter-resistant glass.
This heater is preset to 78˚F and is accurate to plus or minus 1˚F. It features a red indicator light to let you know when it’s actively heating. It includes a safety feature that causes the heater to shut off if it senses it is no longer submerged.
This heater must be fully submerged at all times to work properly. It is not made from shatterproof glass and may be damaged if dropped or handled roughly. It is made to be installed vertically only and is not recommended for horizontal use. This heater often is not able to fully heat to the appropriate water temperature.
Did these reviews help narrow your options for choosing a new aquarium heater?
The best overall pick is the Aquatop Submersible Glass Aquarium Heater, but it’s closely followed by the premium Cobalt Aquatics Electronic Aquarium Heater and the best value Tetra HT10 Submersible Aquarium Heater. These three are the best picks out of the 10 products reviewed, but all 10 products have plenty of strong points!
Finding the right aquarium heater for your tank will ensure the health and safety of your fish, plants, invertebrates, and even corals. There are options here for tanks from 1.5 gallons to 100 gallons or more, so there are great options for almost any tank setup.