Anyone who has ever owned an aquarium will tell you that it is a beautiful addition to your home. There is nothing more relaxing than sitting back while you watch your fish swimming around in their little aquatic environment. An aquarium can be a focal point in your home and a great conversation starter when guests drop in. They are also a great way to keep the kids entertained and teach them a little bit about the responsibility of caring for their pets.
An aquarium’s beauty is that you control the conditions to recreate almost any sort of aquatic environment. With an aquarium heater, you can safely manage a tank full of tropical fish no matter how cold your own climate is. The best aquarium heaters will give your collection of fish a happy home, and we’ve found great options. So, dive in! It’s time to create that relaxing, aquatic oasis in a tank.
The Best Aquarium Heater
Create a happy and healthy environment for your little aquatic friends with this Orlushy Submersible Aquarium Heater. This aquarium heater is fully submersible and is made from thermal shatter-resistant quartz glass to prevent nasty accidents. It has an automatic safety shut-off feature and overheating protection that also includes fire retardant padding.
All you need to do to get the temperature in your aquarium to a comfortable one for your fish is to set the temperature using the control knob. The indicator light will let you know it’s working, and simply attach it to the tank’s side with the suction cups.
For more must-have products for fish keepers, check out our list of the best aquarium air pumps.
Fully submersible aquarium heater
Made from thermal shatter-resistant quartz glass
Automatic safety shut-off & overheating protection
Designed to absorb impact
Suction cup installation
Fire retardant padding
- Weight15.2 ounces
Explosion-proof & anti-cracking glass
Indicator lamp & Temperature control knob
Suitable for Marine Saltwater and Freshwater
Thermostat may not be reliable
Not all fish can live in the same environment, and the wrong temperature can be devastating to your fish’s health. Too cold and they’ll freeze, too hot and you risk turning your aquarium into a hot pot. The Tetra HT Submersible Aquarium Heater ensures your aquarium is always at the optimal temperature for your fish. It is simple to use, and the thermostat turns off when the temperature is right. The indicator light will display when the heater is working to warm the water and also when it has shut off.
This aquarium heater requires no adjustment. It is heat and shock resistant with aluminum oxide crystals to prevent it from overheating. Simply set the temperature settings to the right one for the type of fish you have and let the heater keep their water just right.
Aquarium heater with electronic thermostat
Heat and shock-resistant
Aluminum oxide crystals prevent overheating
Automatically maintains water temperature
- Weight8.8 ounces
Simple to use aquarium heater
Indicator light show when water is being heated
No temperature adjustment required
Choosing right size for your tank is crucial
Different fish require different water temperatures, so ensure the water in your aquarium is perfect for your fish with this Hygger 500W 300W Aquarium Heater. This is a fast heating submersible thermostat heater suitable for a goldfish tank with a volume of between 30 and 120 gallons.
This heater’s glass tube is made from high-quality explosion-proof quartz, and the external LED digital display shows you the temperature and when the heater is actually heating. Auto shutoff prevents overheating, and the entire heater is easy to clean for happy, healthy fish.
Fast Heating Submersible Thermostat
Suitable for Fish Tank 30-120 Gallon
External LED Digital Display
Temp Controller and Thermometer
High-quality explosion proof quartz glass tube
- Weight2.3 pounds
Fully automatic control
Auto-shutoff prevents overheating
Easy to clean
Thermostat is temperamental
This Fluval E Electronic Aquarium Heater for your aquarium will make caring for your fish easy. This is a fully submersible aquarium heater with an LCD display that shows the actual water temperature so you can be sure your fish are comfortable. It will alert you if the water temperature gets too high or too low, and fish are protected from the heater core thanks to the protection guard.
These fully submersible aquarium heaters are ideal in any climate with precise temperature adjustment. They are easy to mount inside the tank and simple to use. Just set your temperature and enjoy watching your fish.
Fully submersible aquarium heater
Advanced fish protection with guard
Easy to use adjustment lever
High/low temperature alert
Convenient mounting bracket
- Weight1.05 pounds
LCD displays actual water temperature
Precise temperature adjustment
Fish protected from heater core
You’ll need to experiment with the settings
You don’t need to have an enormous aquarium for your tropical fish. All you need is one of these freshwater and saltwater aquarium heaters like this Orlushy Mini Aquarium Heater. This one is ideal for fish bowls or tanks from 3 to 15 gallons. It is safe, easy to use, and you can set the temperature in the palm of one hand.
This is a heater and thermometer combined into one with an external temperature controller and a built-in aquarium thermometer for extra convenience. The LED digital display shows you the water temperature so you can keep your fish comfortable all year round.
Small FishTank Heater Suitable for 3-15 Gallon
LED digital display
External temperature controller
Suitable for freshwater and marine aquariums
- Weight8.78 ounces
Safe and easy to use
Heater & thermometer combined into one
Set temperature with one hand
Accuracy may be a little off
Create the perfect swimming environment for your aquatic inhabitants with this VIVOSUN 300W Aquarium Heater. This heater offers precise temperature control with an adjustable temperature from 20 to 34°C, so you can check the optimal temperature for the type of fish you have and adjust the heater accordingly.
This exceptional aquarium heater is titanium tube materials and is ideal for use in fresh and saltwater. The intelligent IC chip controls the heater temperature, and you can check the heat via the display and intelligent indicator light.
Precise temperature control
Adjustable temperature from 20 to 34 °C
Intelligent Indicator Light
2 stable suction cup angles
Titanium tube material
For use in fresh and saltwater
- Weight13.6 ounces
Intelligent IC chip controls heater temperature
Anti-flaming heater cover
Easy to set temperature
Easy to install
May need to be replaced within a year
The FREESEA Aquarium Heater is a tiny heater for small tanks between 1 to 10 gallons. This makes them ideal for a child’s first fish tank or those with limited space. It has a temperature range of between 59°F~94°F, an LED temperature display, and an automatic constant temperature function.
Submersible aquarium heaters like this one are simple to use with a real-time temperature display and touch button, and cyclic temperature adjust that is safe and easy to use. Best of all, you won’t need a separate thermometer as this unit is a heater and thermometer in one.
To make taking care of your fish a breeze, choose any of these reliable automatic fish feeders.
Temperature range: 59°F~94°F
LED Temperature Display
Automatic constant temperature function
Touch button, cyclic adjust temperature
Real-time temperature display
Ideal for small tanks 1 – 10 gallons
- Weight8.01 ounces
Thermometer and heater in one
Safe and easy to use
Must be completely submerged
Simplicity is key for aquarium heaters, and this Fluval M Submersible Heater is very easy to use. It is a 200-watt submersible heater, designed for aquariums or betta fish tanks up to 65 gallons. It features a computer calibrated thermostat with an easy to adjust temperature control. The sleek and compact design has a mirrored finish that seamlessly blends into the aquarium’s surroundings and is suitable for freshwater and saltwater aquariums.
200-Watt submersible heater
Designed for aquariums up to 65 gallons
Easy-to-adjust temperature control dial
Sleek and compact design
For use in freshwater and saltwater aquariums
- Weight6.4 ounces
Seamlessly blends into surroundings of aquarium
Sleek and compact design
Easy to adjust temperature
Temperature may fluctuate without warning
Your fish will never know they are in an enclosed aquarium when you make them feel completely comfortable and at home with the Hygger Fast Heating PTC Aquarium Heater. This aquarium heater is stable for freshwater tanks between 60 to 180 gallons with accurate temperature control from 70°F to 94°F. It features IP68 100% waterproof core, and the serrated protective guard prevents fish and other aquatic creatures from getting to the heating core.
This exceptional quality aquarium heater has a digital LED display that shows real-time water temperature, and there is also an error code warning in case something isn’t quite right.
Suitable for 60-180 Gallon Freshwater Tank
Accurate temperature control from 70°F to 94°F
IP68 100% Waterproof
Serrated protective guard
Digital LED real-time water temperature
Premium semiconductor ceramic material
- Weight2 pounds
Run dry and overheat protection
Easy to set temperature control
Error code warning
Freshwater tank only
A happy home equals a happy fish, so transform that cold aquarium into a cozy environment for them to swim around in with the FREESEA Aquarium Heater With Submersible Thermometer. This is a 100% submersible aquarium heater with a temperature range of between 63°F~95°F. It features the automatic constant temperature function to ensure a stable temperature for your fish. As it is a heater and thermometer in one, you can monitor the temperature and make adjustments as needed.
There is an indicator on/off light, so you know when the water is being heated. The display on this heater is easy to read and adjust, and different wattages are available, depending on the tank’s size.
If you want only the best for your pets, don’t forget to also check out these best-selling aquarium filters.
100% submersible aquarium heater
Temperature range: 63°F~95°F
Automatic constant temperature function
Indictor on/off light
Easy to read display
- Weight8.01 ounces
Available in different wattages for different size tanks
Easy to adjust temperature control
Heater and thermometer in one
Must be correctly submerged to avoid damage
Aquarium Heater Buying Guide & FAQ
Features to Look for in Aquarium Heaters
Power - Choosing an aquarium heater largely depends on your tank's size, and from this, you will find what wattage your aquarium heater needs to be. If the wattage is too high, you may overheat your tank, and vice-versa. Check the dimensions and volume of your aquarium before you choose a heater. Then check the specifications to ensure the aquarium heater is suitable for a tank of that size.
Adjustable Temperature - The environment in your aquarium changes in much the same way as it does in your home. There will be days when you need to adjust your home's thermostat, and the same applies to your aquarium. The temperature setting will mainly depend on the type of fish you have. Adjustable temperature is crucial to ensure your fish's health, so keep this in mind and adjust the temperature as needed.
Controls – Pay attention to where the temperature controls are. Are they above the surface of the water or outside of the tank? Or are they submerged in the tank with the actual heater? If your controls are submerged, you really want to make sure the buttons or dials are a decent size that makes it easy to adjust in water.
Temperature Readability - Some fish species are more sensitive to temperature fluctuations than others, so they will rely on you to keep an eye on the temperature in the tank to ensure their health and well-being. To do so means checking the temperature gauges at least a few times a day. Some aquarium heaters have a thermometer built into the actual heater, while others have a separate temperature display. The only important factor here is that you can easily read the temperature, and therefore act quickly if the temperature has changed drastically.
The temperature gauge on aquarium heaters may not always be accurate, which could spell disaster. Always keep a backup thermometer close to your tank, and check the water temperature manually at least once a day.
Safety Features - Whenever you are dealing with a device or appliance with an electrical supply and will be submerged in water, you need to ensure that this item is safe to use. In the case of an aquarium heater, you want it to be safe for you and your pets. Some of the more important safety features of an aquarium heater include:
- Fish/Heater guard - There should be a guard similar to a cage surrounding the heating core. The holes should allow for water to flow through but small enough to prevent your fish from coming into contact with the core.
- Automatic On/Off Switch - Over time, you may experience issues with your aquarium heater, which could involve overheating. Look for a heater with an automatic on/off switch that will prevent the heater from overheating and bringing the water to an excessively high temperature. You also want this switch to turn off if the tank water evaporates and exposes the heater.
- Light Indicator - The light indicator on aquarium heaters let you know when the heater is on and when it switches off. The best aquarium heaters will have this light indicator. The thermostat will allow the heater to bring the water to a set temperature then turn off automatically until the temperature drops.
Aquarium Heater FAQ
Q: How do aquarium heaters work?
A: Aquarium heaters work using electricity to power the heating core. The heating core heats the water around it quickly as water can absorb heat with extreme efficiency. This is not enough, though. If the only water being heated is around the aquarium heater, your tank will end up with a hotspot; the water circulation is essential to maintain a stable temperature in all areas of the aquarium. This stability is achieved via the tank's filtration system.
Q: Where should I place my aquarium heater?
A: The first rule of thumb with an aquarium heater is the need for it to be completely submerged. Some heaters will mount inside the tank vertically, others horizontally, or both. Place the aquarium heater in an uncluttered corner of the tank away from greenery or decorations so that nothing will interfere with the heating core or prevent heated water from properly circulating the tank. Check the instruction manual for the best position for your aquarium heater.
Q: Why do aquarium heaters have to be submerged?
A: Ironically, if an aquarium heater is not adequately submerged in the tank water, it may overheat and short circuit. Choosing the right sized aquarium heater is so vital for this reason. Your heater is fully waterproof and needs to be submerged to work efficiently, but you need to make sure the heater's bottom is not making contact with the rocks on the bottom of the tank. If the rocks get hot, they can cause a crack in the glass, ending in an aquatic disaster.
Q: Can you have the cord of the submersible heater in the water?
A: Yes, and no. First, check your aquarium heater's manual and care instructions to determine if your model (including the cord) is fully waterproof. The spot where the cord joins with the heater unit join will be waterproof, so parts of the cord are submersible on every model listed in this guide.
Q: How safe are aquarium heaters?
A: Aquarium heaters are electrical appliances that are constantly submerged in water, so the risk of something going wrong is genuine. However, if you ensure the heater has been properly installed and take adequate precautions, aquarium heaters are perfectly safe.
Before you rush out and buy those beautifully colored fish you've always wanted, make sure you understand the type of environment and water temperature they are accustomed to living in. Then choose any one of the best aquarium heaters we've featured in this guide and give your aquatic creatures a safe and comfortable home.