To keep your fish alive and healthy, you need to provide the correct environment for them, including the optimal water temperature. As such, you’ll need a reliable aquarium heater. It’s important to pick out the correct water heater that will adequately heat the water in your tank but not overheat it.
We reviewed dozens of aquarium heaters to identify the best of the best. We focused on a range of features, including wattage, heater type, temperature controls, and average customer reviews.
After extensive research, the Hygger Titanium Tube Submersible Pinpoint Aquarium Heater stood out to us as the clear top pick. Its titanium construction makes it virtually indestructible and it gets excellent reviews from people who use it day in, day out.
The 5 Top-Rated Aquarium Heaters
|Best Overall||Hygger Titanium Tube Submersible Pinpoint Aquarium Heater||4.8|
|Runner Up||Cobalt Aquatics 31000 Neo-Therm Heater||4.3|
|Best Budget Buy||Tetra HT Submersible Aquarium Heater||3.8|
|Best Inline Aquarium Heater||ISTA Inline External Heater Aquarium Heater||3.7|
|Best Small Aquarium Heater||SZELAM 25W Mini Fish Tank Heater
*Ratings are from Amazon at the time of publication and can change
Our Top Pick: Hygger Titanium Tube Submersible Pinpoint Aquarium Heater
One of the main concerns about submersible aquarium heaters is that the glass tube can shatter in rare cases, which would generally leave you with a tank of dead fish. The Hygger Titanium Tube Submersible Pinpoint Aquarium Heater is made from titanium, with no glass parts at all, so that’s one less thing to worry about! We’re focusing on the 100 watt (W) model, which is suitable for tanks of between 10 and 25 gallons.
It comes with a digital thermostat that allows you to set a precise temperature between 32 and 104°F. The thermostat shows both the temperature that you’ve set and the current temperature of the water inside the tank, so you can easily see whether the heater is doing its job properly. Accuracy and reliability is key in an aquarium heater, and this one receives consistently good reviews in those areas.
The Hygger is priced at just under $60, which isn’t inexpensive, but provides excellent value when you take quality into consideration.
Hygger Titanium Tube Submersible Pinpoint Aquarium Heater Key Features:
- Accurate to within +/- 0.5° C
- Automatic shutoff when desired temperature is reached
- Can switch between readings in Celsius or Fahrenheit
Our Runner Up Pick: Cobalt Aquatics 31000 Neo-Therm Heater
The Cobalt Aquatics 31000 Neo-Therm Heater is an aquarium heater that doesn’t draw attention to itself. Its slim black design makes it easy to camouflage, plus the fact it’s made from plastic means it’s shatterproof, too.
It’s fully submersible with a thermostat built into the body of the heater, so you don’t need to find a spot to stick an external thermostat. Thanks to the one-touch system, it’s easy to set the thermostat to the temperature you require, plus it’s able to simultaneously display the set temperature along side the actual temperature in the thank. That said, the thermostat isn’t as clear and easy to use as the one on our top pick.
With a price tag of less than $45, it’s less expensive than our top pick, but still on the higher end of the market.
Cobalt Aquatics 31000 Neo-Therm Heater Key Features:
- Heating power of 25W
- Accurate to within +/- 0.5°F
- Temperature range of 66 to 96°F
Best Budget Pick: Tetra HT Submersible Aquarium Heater
If you’re looking for a small, simple aquarium heater at a low price, look no further than the Tetra HT Submersible Aquarium Heater. At just $10, it certainly won’t break the bank, but its 50W power is only suitable for aquariums of between 2 and 10 gallons.
What you give up in exchange for the low price is the ability to control the temperature it heats your aquarium to. This model can only heat water to 78°F (+/-2°F), which is fine for a large number of tropical fish species but certainly not all, so you’ll need to double-check the optimum temperature range for your fish before you buy.
The outer tube is made from glass, which is heat and shock resistant but still not 100 percent resistant to breakages. All in all, it’s fairly reliable and extremely simple to use, but it’s not the most versatile heater on the market.
Tetra HT Submersible Aquarium Heater Key Features:
- Contains silicon carbide crystals for better heat dispersal
- Indicator lights shows when water has reached correct temperature
- Can be mounted vertically or horizontally
Best Inline Aquarium Heater: ISTA Inline External Heater Aquarium Heater
Though far less common than standard submersible varieties, inline aquarium heaters are convenient for anyone who uses a sump or a canister filter. Since you fit them externally, rather than inside the tank, there’s no chance they could scald your fish or shatter inside the tank. The ISTA Inline External Heater Aquarium Heater is an excellent choice for anyone who wants an inline heater.
We’re focusing on the large 500W model that can heat tanks of 65 to 130 gallons and retails at just over $65. You can, however, buy less powerful options, should you have a smaller tank. It features two sensors (one on the inlet and one on the outlet) to closely monitor temperature. Users state it gives extremely consistent results, so it’s great for fish that don’t do well even with small temperature fluctuations. On the downside, however, some buyers report that the connectors leak, though this can be fixed with hose clamps.
ISTA Inline External Heater Aquarium Heater Key Features:
- Doesn’t take up room in the tank
- Easy to set the thermostat
- Temperatures listed in Celsius
Best Small Aquarium Heater: SZELAM 25W Mini Fish Tank Heater
A small tank only needs a small heater, but it still needs to do its job well. If you’re looking for a heater for a tank of up to five gallons, such as a betta fish tank, we’d recommend the SZELAM 25W Mini Fish Tank Heater. It’s durable and extremely simple to use; just attach it to the inside of your tank, plug it in, and it does everything else for you.
This heater automatically sets the temperature between 73 and 82°F, so it’s fine for hardy tropical fish but not great for those that need water at a very specific temperature or can’t deal with occasional fluctuations. The ABS plastic outer won’t scald your fish if they rub up against it and is shatterproof, to help keep the inhabitants of your tank safe. With a price tag of less than $15, this is an inexpensive option for a small aquarium.
SZELAM 25W Mini Fish Tank Heater Key Features:
- Two suction cups for easy fitting
- Automatically turns off when correct temperature achieved
- Comes with free plastic aquarium plants
Who Should Buy an Aquarium Heater
Anyone who keeps fish in an aquarium (with the exception of cold water fish) should buy an aquarium heater. Tropical fish and most common marine fish require warm water in their tanks, which means an aquarium heater is a must-have. Ensuring their water is at the correct temperature is just as important as feeding your fish or keeping their tank clean. If you keep warm water fish without a heater, they’ll soon get sick and die, so it’s not optional!
Even if you keep cool water fish, such as goldfish, you might still want a heater to maintain an even temperature during the cooler months, especially if they’re kept in a chilly room. However, you’ll need to check your chosen heater can be set to low enough temperatures, as many are designed with tropical fish in mind.
Important Features to Consider
An aquarium heater should have a few important features. Here’s what to consider when selecting a heater for your aquarium:
- Type of aquarium heater. The majority of aquarium heaters on the market today are submersible heaters, which can be fully submerged in your tank (but may have an external thermostat). However, you can also find inline heaters and under-gravel heaters. Pick the variety that works best for your setup.
- Wattage. You can find aquarium heaters from as little as 10W to over 1,000W. The larger the wattage, the more powerful the heater. Heaters with a low wattage aren’t powerful enough to heat large tanks and heaters with a high wattage will overheat small tanks, so it’s important to choose a model with an appropriate wattage.
- Material. Traditionally, aquarium heaters have featured heating elements with glass tubes. Although these are generally made from glass that’s undergone a hardening process, there’s still a chance they could shatter, which would likely electrocute the inhabitants of your tank. Newer models can have metal or plastic exteriors, which are less prone to breakage.
- Temperature range. Check whether your chosen aquarium heater has a fixed temperature or you can select the temperature from a range. The latter is a better option, especially if your fish require a slightly lower- or higher-than-average temperature.
- Thermostat. The thermostat is where you select your desired temperature (if you have the option to do so). It can have a digital display with buttons to set it or it can have a dial.
Frequently Asked Questions
What is an aquarium heater and how does it work?
An aquarium heater is a heater designed to keep the water in your fish tank at a specific and constant temperature (though the required temperature depends on what fish you keep). How it works depends on the exact variety you choose, but most feature a heating element that sits inside the tank.
What size aquarium heater do I need?
It’s vital you choose the right size aquarium heater for your tank, but what is the right size? Luckily, most aquarium heaters list what size tank they’re suitable for in the product description. Alternatively, see below for the rough amount of watts you need per gallon.
How many watts does an aquarium heater use per gallon?
A good rule of thumb is 2.5 to 5 watts per gallon of water in your aquarium, but you may need slightly more power if your fish tank is kept in a cold room (since the water will need heating up more due to the low ambient temperature).
How do I know if I need an aquarium heater for my fish tank?
First, you need to find out what water temperature the fish you keep (or intend to keep) require. If the ambient temperature in the room where they’ll be kept ever drops below the temperature your fish need, then you’ll have to buy an aquarium heater to keep the water temperature constant. Unless you live somewhere it’s extremely warm all year round, you’ll need an aquarium heater for any tropical or sub-tropical fish.
Other Aquarium Heaters We Reviewed
We looked at 20 other heaters for aquariums. Even though they didn’t make our 5 best aquarium heaters list, they’re the best of the rest and each is still a great option for your fish tank. The information you’ll need to compare each one is included with the listing.
- Aquarium Heaters 50W and Under
- Aquarium Heaters 51 to 200W
- Aquarium Heaters 200 to 500W
- Aquarium Heaters Over 500W
Aquarium Heaters 50W and Under
- Easy-to-set dial controls
- Suitable for tanks up to approximately 20 gallons
- Temperature range of 59 to 94°F
- Plastic outer protects fish from burns
- Suitable for small tanks
- Provides a constant heat of 78°F
- Accurate to +/-1°F
- Indicator light shows heater is working
- Raises temperature by around 5°F
- Easy to use
- Suitable for freshwater or marine tanks
- Temperature range from 68 to 93°F
- Double thermal insulation
- Also acts as a thermometer
Aquarium Heaters 51 to 200W
This slim 150W aquarium heater is easy to set, though it would benefit from a digital temperature display.
- Virtually-indestructible plastic housing
- Indicator light shows when at correct temperature
- Auto-shutoff feature
- Temperature control dial
- Temperature range between 65 and 93°F
- Accurate to +/-1°F
- 200W power
- Extra thermostat to monitor temperature
- Sturdy construction
- 100W heater suitable for 15 to 30 gallons aquariums
- Temperature range between 68 and 89°F
- Comes with two suction cups
- Easy to adjust anywhere from 61 to 90°F
- Suitable for tanks between 26 and 52 gallons
- Comes with peel and stick thermometer
- Simple dial controls
- Indicator light shows when correct temperature is reached
- Can be mounted horizontally or vertically
Aquarium Heaters 201 to 500W
- 300W of power
- Temperature range of 68 to 93°F
- Adjusts with the use of a dial
- Easy-to-read digital display
- Set temperature anywhere from 68 to 93°F
- Suitable for aquariums up to 100 gallons
- Temperature range of 61 to 90°F
- Suitable for freshwater and saltwater tanks
- Accurate within +/-2°F
- Durable milky quartz tube
- Protective casing
- Temperature range 69 to 94°F
- Shatterproof design
- Comes with floating thermometer
- Adjustable between 65 and 93°F
- Dial control
- Comes with temperature probe
Aquarium Heaters Over 500W
- Easy-to-use temperature control dial
- Temperature range of 72 to 93°F
- Suitable for aquariums up to 265 gallons
- Set temperature anywhere between 0 and 99°F
- Accuracy +/-2°F
- Great for long aquariums as you can place one heating element at each end
- Temperature range of 68 to 95°F
- Accuracy +/-2°F