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Tropical fish need a heater in their tank to keep the temperature of their tank at a warm and consistent level. However, choosing the best aquarium heater can be confusing as there is so much that you need to consider, such as the heater type, wattage, quality, and temperature range.
It can certainly get quite complicated! Back when I started keeping fish (well over a decade ago), I was completely lost when it came to selecting the right heater for my tropical tank.
I actually ended up using one that was considerably underpowered for the size of my tank, which led to my fish nearly freezing.
That’s why I’ve composed this guide to help aquarists going through a similar dilemma and make sure they don’t make the same mistake as I did.
So, if you’re looking for the best aquarium heaters or simply want a little advice on how to choose the correct one for your aquarium, you’re in the right place!
On to the Reviews…
Fluval M200 Submersible Heater
This submersible aquarium heater from Fluval is suitable for both freshwater and saltwater fish tanks up to 65 gallons in capacity. It has a modern, space-saving, and mirrored design to make it less visible in your setup.
Top Pick: Fluval M200 Submersible Heater
One of the best aquarium heaters to use for your tank is the Fluval M200 Submersible Heater, which is suitable for both freshwater and saltwater setups.
Fluval is well-known in the fishkeeping hobby for consistently delivering top-quality aquarium products and equipment, so this Fluval heater is definitely one you can rely on!
The heater is ideal for aquariums up to 65 gallons in size as it is rated for 200 watts. It sports a compact and modern design, allowing it to blend into your tank without taking up too much space.
I really like the mirrored appearance of this heater as it reflects your setup’s surroundings, which almost makes it look invisible.
The heater features a computer-calibrated thermostat and an adjustable temperature dial (range from 66 to 86 degrees Fahrenheit) that is easy to control, too!
The only downside of this heater is that the thermostat can sometimes display a different temperature than the thermometer. However, the difference is quite minor (a few degrees off at most), so I don’t think it’s a huge problem for an otherwise quality heater.
You could also use a separate thermometer to double-check the temperature.
Specs
- Wattage: 220W
- Weight: 10.57 oz
- Dimensions: 1.7” x 4.8” x 26.5”
Pros
- Ideal for larger tanks
- Wide temperature range
- Compact and mirrored design
- Computer-calibrated thermostat
Cons
- Thermostat can sometimes be inaccurate
EHEIM Jager Aquarium Thermostat Heater
If you’re on the hunt for a budget-friendly but high-quality fish tank heater, this one from EHEIM is an excellent option. It’s durable, safe, and reliable to keep your tropical aquatic pets at a comfortable water temperature.
Best Value: EHEIM Jager Aquarium Thermostat Heater
The EHEIM Aquarium Thermostat Heater is the best aquarium heater if you need something that’s both top quality and affordable. It’s made from durable and shock resistant glass that’s suitable for freshwater and saltwater fish tanks.
My favorite feature of this particular heater is its thermo safety control, which helps protect the unit from running dry. The device will automatically turn off if the water level drops too low, which is useful if you forget to turn off the heater during a water change!
The heater is fully submersible and boasts a TruTemp dial that recalibrates the unit for reliable, proper temperature control. It also has an on/off indicator light so you know when the device is actively heating.
However, the temperature dial on this EHEIM heater can be a little hard to turn as it’s quite stiff. The thermostat can also be inaccurate, so I’d recommend using a separate one just to be on the safe side!
Specs
- Wattage: 125W
- Weight: 0.62 lbs
- Dimensions: 1.42” x 12.56”
Pros
- TruTemp dial
- Indicator light
- Thermo safety control
- Made from shatterproof and shock resistant glass
Cons
- Thermostat can be unreliable
- Adjustable dial can be hard to turn
Finnex Digital Heater Controller
The Finnex Digital Heater is a great choice for larger tanks up to around 120 gallons due to its high wattage and quality. It boasts a sturdy titanium tube and comes with a range of features like a digital controller and built-in memory system.
Editor’s Choice: Finnex Digital Heater Controller
One of my personal favorite heaters to use is the Finnex Digital Heater as it is unbeatable in terms of quality and durability. I have this heater in both my saltwater setup and freshwater tank, and it works spectacularly.
It’s 300 watts (higher wattages are also available), so it’s the best aquarium heater for large tanks, particularly those that contain aggressive species due to its strong titanium heating element tube.
The main reason why I like this electronic heater so much is the digital controller it comes with, which allows you to increase/decrease your tank temperature with pin-point accuracy.
It also has a temperature range of between 0 to 99 degrees Fahrenheit, which is considerably wider than most aquarium heaters. Another great feature of this heater is that it has a built-in memory so it can restore your set temperature if there is a power outage.
Last but not least, the Finnex Digital Heater has an auto shut-off feature to protect it from overheating. If the water temperature is higher than your set temperature, it will automatically turn off and stop heating your tank.
The only downside of this aquarium heater is the short length of the temperature sensor and heating tube cords (around 48 inches in length). However, this can easily be solved with an extension cord!
Specs
- Weight: 2 lbs
- Wattage: 300W
- Dimensions: 13” x 7.5” x 2.5”
Pros
- Built-in memory
- Strong titanium tube
- External digital controller for ease
- Automatically turns off if temperature gets too high
Cons
- Heater and temperature sensor cords are quite short
Hygger 200W Aquarium Heater with External Digital Controller
This submersible aquarium heater from Hygger is a decent choice for medium-sized tanks. It comes with a range of handy features like an indicator light and external temperature controller.
Hygger 200W Aquarium Heater with External Digital Controller
Next up is the Hygger 200W Aquarium Heater, which comes with an external digital controller to help you keep your fish tank at a stable water temperature. It’s made from high-quality quartz glass which is wrapped in a heater guard to protect your fish from burns.
The heating element is resistant to both explosions and corrosion, making it very safe for your fish. One of the best aspects of this fully submersible heater is the external temperature controller it comes with, allowing you to easily monitor the warmth of your tank.
It boasts a wide temperature range of between 61 to 90 degrees Fahrenheit. The heater is also conveniently installed with indicator lights that flashes red when it is heating and yellow once the desired temperature has been met.
Unfortunately, the heating element can fail prematurely (in some cases, within a year of use). In addition, the provided suction cups are a little weak to hold up the unit properly.
Specs
- Wattage: 200W
- Weight: 2.07 lbs
- Dimensions: 12.56” x 8.31” x 3.07”
Pros
- Indicator light
- Comes with a heater guard
- Made from durable quartz glass
- Includes an external temperature controller
Cons
- Suction cups are a little flimsy
- Heater fails prematurely in some cases
Fluval E200 Advanced Electronic Heater
If you’re looking for a good-quality fully submersible heater, this one from Fluval is well worth considering. It sports dual temperature sensors, fast-heat technology, a heater guard, and colored display alert system.
Fluval E200 Advanced Electronic Heater
Another one of the most popular aquarium heaters (and best!) is the Fluval E200 Advanced Electronic Heater, which can be adjusted in 0.5-degree increments for an accurate temperature setting.
It has dual temperature sensors for precision and reliability, alongside a fast-heat technology to ensure your tank quickly heats up to your desired temperature (between 68 to 93 degrees Fahrenheit).
I really like that this glass heater is installed with an auto turn-off system for safety once your tank reaches the right temperature.
The heater also comes with a guard to prevent your fish from coming into contact with it and a low-profile mounting bracket for easy installation.
Due to the heater’s colored display alert system, you can quickly identify if the temperature of your tank drops or rises more than 5.5 degrees as it will flash! The reader can even be set to measure temperature in either Celsius or Fahrenheit.
The main issue with this fully submersible aquarium heater is that it can sometimes struggle to maintain the heat in tanks over 25 gallons (you may need to set the temperature on the unit higher).
The thermometer and thermostat can also both give different readings, so it may be worth using a separate thermometer.
Despite these couple of flaws, the heater comes with a whopping 5-year warranty, so any faults with the unit will be covered by the manufacturer!
Specs
- Wattage: 100W
- Weight: 1.01 lbs
- Dimensions: 1.8” x 3.3” x 17”
Pros
- Comes with a heater guard
- 2 temperature sensors for accuracy
- Colored display with a built-in alert system
- Temperature can be adjusted in 0.5-degree increments
Cons
- Can struggle to heat tank sizes over 25 gallons
- Thermostat and thermometer can give different readings
Aqueon Pro 300 Submersible Heater
This 300-watt submersible tank heater from Aqueon is one of the best aquarium heaters for large setups. Its temperature can be adjusted in 1-degree increments and it comes with a protective casing, suction cups, and an auto shut-off system.
Aqueon Pro 300 Submersible Heater
If you’re looking for a great heating unit for a large aquarium, you can’t go wrong with the Aqueon Pro Adjustable Heater, which is rated for 300 watts.
It’s fully submersible with temperature settings of between 68 to 88 degrees Fahrenheit that can be adjusted in 1-degree increments. You get a protective casing with the heater and a sturdy mounting bracket for simple installation.
The heating system features an auto shut-off when it overheats to keep your fish safe (it also resets once it has cooled down). Best of all, it’s so you know when the actual heating element is actively working.
However, the thermostat on this heating unit can be inaccurate (sometimes up to a few degrees off), so I’d recommend using an aquarium thermometer to double-check the temperature of your tank water.
Specs
- Weight: 12 oz
- Wattage: 300W
- Dimensions: 1.5” x 1.5” x 15”
Pros
- Auto shut-off system
- Comes with a protective wrap
- Sturdy suction cups for easy setup
- Ideal for large acrylic or glass tanks
Cons
- Thermostat can be inaccurate
HITOP PTC Adjustable Aquarium Heater
This reliable heater from HITOP is a good pick for aquarists with a medium-sized or large setup. It comes with a protective cover, auto turn-off system, adjustable temperature dial, and thermometer.
HITOP PTC Adjustable Aquarium Heater
The HITOP PTC Adjustable Aquarium Heater is a fantastic selection for a freshwater or saltwater aquarium that’s on the larger side as it’s 300 watts. It’s completely shatterproof and comes with a protective cover for safety.
It sports a PTC ceramic heating element, which means it uses a positive temperature coefficient thermistor. This allows for fast heat transmission, good insulation, and enhanced durability.
You can adjust the heater’s temperature from 63 to 90 degrees Fahrenheit, which is a pretty big range compared to some other heaters! Once the unit reaches desired heat, it will automatically turn off to prevent overheating.
You also get a stick-on thermometer and 4 suction cups with the device for easy monitoring and installation.
Although this heater works well for the most part, its thermostat can be inaccurate and display a different reading than the included thermometer. The suction cups are also a bit flimsy and weak.
Specs
- Wattage: 300W
- Weight: 13.44 oz
- Dimensions: 11.4” x 1.2” x 2.2”
Pros
- Shatterproof
- Protective casing
- Wide temperature range
- Comes with a thermometer
Cons
- Flimsy suction cups
- Thermostat can be unreliable
Tetra HT Submersible Aquarium Heater
This Tetra heater is a solid choice for a nano aquarium, with the bonus of being budget-friendly. It’s preset to 78 degrees Fahrenheit, which is ideal for most tropical fish species.
Tetra HT Submersible Aquarium Heater
Last but not least in this aquarium heater reviews guide is the Tetra Aquarium Heater, which is an ultra affordable option for aquarists on a budget.
It sports a sleek and compact design, which makes it easy to hide behind plants and aquarium decorations. For this reason, I think it’s a great choice for a nano aquarium.
It also has indicator lights so you know when the unit is on – if the light is red, it’s actively heating, and if it is green, that means the device has finished heating!
However, the temperature is preset to 78 degrees Fahrenheit, so you can’t lower or increase it, so this is something to be mindful of if you own species that need cooler or hotter water.
In addition, the heater can struggle to heat aquariums over 10 gallons, so it’s best used for smaller setups.
Specs
- Weight: 8.8 oz
- Wattage: 100W
- Dimensions: 1.63” x 3.5” x 8.25”
Pros
- Indicator lights
- Ideal for small tanks
- Sleek and compact design
Cons
- Temperature cannot be adjusted
- May be unsuitable for tanks over 10 gallons
Do Fish Tanks Really Need Heaters?
Fish tanks containing tropical fish require heaters to keep the water temperature warm and prevent any cool spots from forming.
Cold water fish like goldfish don’t need a heater unless you live in a cool climate.
In larger tanks, you may need to use multiple heaters (usually two heaters will suffice – one on each end of the tank) to ensure your aquarium water maintains a stable warmth and doesn’t get cold in a particular area.
What Are the Benefits of Using an Aquarium Heater?
The main benefit of using a heater is that it keeps your aquarium water at a consistent and warm temperature. This is useful for preventing temperature fluctuations, even if the outside temperature drops.
An aquarium heater is also mandatory for keeping tropical fish that require warm water to survive.
What Is the Best Heater for My Fish Tank?
This mostly depends on the type of setup you have, but a submersible fish tank heating device is a good choice for most standard aquariums.
Submersible aquarium heaters are by far the most popular choice in aquariums, and are pretty reliable, accurate, and sturdy (particularly those made from titanium).
However, if you have a heavily planted tank, a substrate heating system may be a better choice to help encourage plant growth.
What Are the Different Types of Aquarium Heaters?
There are many aquarium heater types you can use for your tank, each with their advantages and disadvantages.
I’ll be explaining a little about each variety below to give you a good idea on which type to choose for your specific setup.
Immersible Heaters
An immersible heater, also known as a hanging heater, is a type of external heater that is clipped onto the edge of your aquarium, usually at the back.
The heating element (normally a glass tube) of immersible aquarium heaters is placed inside your tank.
If you’re using an aquarium hood, you’ll need to cut a hole into it (some hoods come with pre-cut openings you can pop out) in order for the heater to fit.
NOTE
Immersible heaters are best used for freshwater setups as the salt from brackish or marine setups can leach into the glass tube and corrode it.
In-line Heaters
In-line aquarium heaters are another type of external heater, but they are fitted inside plumbing of aquarium equipment, like canister filter tubing.
This type of heater warms up the water before it is deposited back into the aquarium through the water pump.
Unlike other heaters, an in-line heater requires a water pump to work, but this can be done via a canister filter, UV sterilizer, or trickle filter.
Submersible Heaters
A submersible fish tank heater needs to be placed inside your aquarium water, ideally horizontally, but it can also be positioned vertically or at an angle.
This type of heating unit is normally attached via suction cups on the tank glass.
Substrate Heaters
Substrate heaters are popular in heavily planted aquariums as they help keep the substrate warm to promote healthy plant roots. They consist of a coiled wire or wire grid that is positioned underneath the substrate.
In-Filter Heaters
The last type of heater you can use for an aquarium is an in-filter heater. This type of heater is built into a filter, typically an external filter like a canister filtration system.
As the water passes through the filter, the heater warms it up before it is deposited back into the tank.
FAQs About Aquarium Heaters
Below I’ll be answering some frequently asked questions regarding aquarium heaters!
How to Setup Aquarium Heater
While setup will vary depending on the type of fish tank heater you’re using, for most heaters, you should place your heater near your filter inlet/outlet.
Submersible heaters are more effective when positioned horizontally, but they can also be placed vertically if you prefer.
Make sure you don’t turn on your heater (for those that are submersible or partially submersible) until it is fully immersed in water, otherwise it can overheat and break.
Once the heater has been placed inside your aquarium, turn it on and set it to your desired temperature.
External heaters like in-line heaters should be placed outside the tank, usually inside or along the output tubing of your canister filter.
Can Aquarium Heaters Burn Fish?
Yes, aquarium heaters can burn fish if they rest on top of it or press against it for an extended period. One of my betta fish used to do this until I started using a heater guard.
A heater guard can help protect your fish from burns and discourage them from going near your heater, so it’s a really good tool to use in your tank.
What Size Heater for an Aquarium?
You should aim to use a heater with a wattage of between 2.5 to 5 watts per gallon of aquarium water. It’s best to use 5 watts per gallon if you need to heat 10 degrees higher than room temperature water or your aquarium is fitted with a cover/hood.
In large tanks, you may need to use two heaters to ensure it maintains consistent warmth without any cold zones.
This table should give you a good idea on which size heater you need for your setup.
| Heater Wattage | Tank Size |
| 12.5 to 25 Watts | 5 Gallons |
| 25 to 50 Watts | 10 Gallons |
| 50 to 100 Watts | 20 Gallons |
| 100 to 200 Watts | 40 Gallons |
| 150 to 300 Watts | 60 Gallons |
| 250 to 500 Watts | 100 Gallons |
Can Aquarium Heaters Be Fully Submerged?
Most types of heaters can be fully submerged – in fact, they need to be completely submerged to work effectively and prevent breakage.
However, some heaters can only be partially submersible, and some need to be placed outside the tank, such as a hanging heater and in-line heater.
Can an Aquarium Heater Be Too Powerful?
Yes, an aquarium can be too powerful if the wattage is too strong for the size of your tank.
Using a heater with a significantly higher wattage than what is appropriate for your tank size could drastically increase the temperature of your aquarium to dangerous levels.
As a general rule of thumb, you need 2.5 to 5 watts of heat per gallon of water. If you want to increase the temperature of your aquarium by around 10 degrees above air temperature, opt for a heater on the higher end of the recommended guideline.
Are Titanium Aquarium Heaters Better?
Titanium aquarium heaters are much more durable and effective at transmitting heat than glass heaters.
They are less likely to break and will not shatter, unlike glass heaters, too. This makes them a great option for large fish like oscars.
However, titanium fish tank heaters are usually on the pricey side, so they may not be ideal for aquarists on a budget.
Does a Fish Tank Heater Use a Lot of Electricity?
This mostly depends on the wattage of the unit and its set temperature, alongside the size of your aquarium. Bigger tanks will take longer to heat and maintain warmth than smaller aquariums, which will drive up the cost of running a heater.
In addition, aquarium heaters with a higher temperature and wattage will use more electricity than units with lower temperatures and wattages like nano fish tank heaters.
It’s important to note that fish tank heaters are usually only on for around half a day as most models automatically switch off once the desired warmth has been met.
Final Thoughts
- Mirrored and compact design
- Wide water temperature range
- Computer-calibrated thermostat
- On/off indicator light
- Shatterproof and shock resistant glass design
- Automatically switches off if water level drops too low
- Built-in memory
- Durable titanium tube
- Auto turn-off feature if water temperature rises
I hope you found this guide on the best aquarium heaters helpful and were able to choose the right one for your fish tank!
Although there are a lot of different types of heaters, if you have a standard aquarium with small tropical fish, a submersible heating unit is a good option.
Which product do you think is the best fish tank heater? I’d love to hear your thoughts on our social media platforms (and some pics of your tank!). Be sure to share this post with your friends and family so they can learn more about aquarium heaters, too.
Thanks For Reading!
Thanks for taking the time to read this review, and I trust you have discovered the ideal aquarium heater for your tank.
If you think this post might be helpful to your friends, please don’t hesitate to share it with them. And remember to check the site for information about fish care guides and aquarium product reviews.
