A tank heater is a piece of essential equipment for an aquarium. It will help you keep the fish tank water warm and stable, which can prevent your fish from getting diseases and make them live longer.
Especially in winter, you need to use a heater to raise the water temperature in your tank so that your fish can enjoy a healthy life.
So undoubtedly, heaters are an essential part of any aquarium. But when it comes to small aquariums, it can be tough to find a heater that is both affordable and effective.
Thatâs why Iâve put together this list of the six best small aquarium heaters. These heaters will perfectly fit in your nano tank and keep it at a comfortable temperature without breaking the bank.
So, whether youâre just starting out with fishkeeping or youâre looking for an upgrade, check out my picks for the best small aquarium heater.
How To Choose The Right Size Of Aquarium Heater
The power of an aquarium heater is measured in watts (W). For instance, a 20-watt unit will heat up your aquarium twice as fast as a 10-watt one. So if you have a big tank, get yourself some higher-powered gear.
The rule of thumb is that you would need 2.5 to 5 watts for one gallon, which means if your tank holds 10 gallons and your heater has a power rating higher than 25W, then it will efficiently heat up the water in the tank without too much trouble!
However, thereâs more than just size when considering how well these things work; environmental factors such as ambient temperature also come into play here.
Small Heaters Types
There are two main categories in the world of small aquarium heaters â preset and adjustable.
A small fish tank heater will be either a preset type or one that has an adjustable temperature controller.
Preset Aquarium Heaters
These models typically have an âalways-onâ design and will not turn off until the temperature reaches 78 degrees Fahrenheit (26 Celsius).
One of the best things about preset heaters is their size. They donât require a thermostat, so manufacturers can create some unbelievably slim and small aquarium heater models!
But preset heaters are not so accurate in maintaining fish tank temperature. An added temperature controller can help regulate the precise temperature and provide safety features.
You can not adjust them â you are at the grace of your heating system. You do not have to go far to find horror stories of preset heaters accidentally killing fish.
As you know, the fish tank water temperature vastly depends on the environment temperature. So on a hot summer day, preset heaters will likewise enhance the temperature of your tank, nonstop â which might be too hot for your fish.
If you have a tiny aquarium with less than 3 gallons of water, a small preset heater will give you more space in the tank.
Adjustable Aquarium Heaters
You can set the water temperature within a defined range with an adjustable heater. You can regulate your water temperature with such a heater, which has the added benefit of keeping the water temperature as your fish need.
These usually come in a bit larger sizes than those of preset heaters but offer more features like shutting off when it reaches your desired temperature level or adjusting its operation based on how cold things get outside!
The ideal temperature for your fish tank is between 66 â 96 degrees Fahrenheit. Still, many people want colder or warmer water as they might have particular kinds of fish species with different needs. This type of heater allows you to set the desired range, and it will maintain that level with precise control!
Also Read: How Do I Know If My Aquarium Heater Is Working
Best Small Aquarium Heater: 6 Top Picks Reviewed
FREESEA Mini Aquarium Heater
- â Temperature range: 59°F~94°F, display Fahrenheit °F, this heater is designed for1~10 gallons tank. Upgrade...
- â Automatic constant temperature function, when water temperature reaches to specified temperature value, heater will...
- â Touch button, cyclic adjust temperature , easy to use and Safety.
- â ăNoteă:this heater is 100% submersible use only, during its heating time, heater must be 100% submerged into the...
- â ăSATISFACTION GUARANTEEDăGain the confidence to go hard with us! Our Aquarium Heater is built with durability in...
FREESEA Mini Aquarium Heater is a new product of FREESEA. It can automatically control the temperature of your aquarium so that you do not need to worry about the temperature difference between winter and summer.
It can make your fish feel comfortable. Its unique design makes its heating area more extensive than other heaters, which will make the water temperature more stable.
Youâll be surprised at how stylish this small heater looks in your nano tank! The longest part of these heaters is 3.5 inches long, which means you can fit these bad boys perfectly in your nano tank.
It has a large LCD screen to clearly show its working state and parameters. In addition, it features auto shutting off once it reaches this desired level of temperature!
This aquarium heater may not be a good fit for tiny tanks such as the 2-gallon one, as it could prove too powerful!
Pros
- 1 Year Warranty.
- Small and compact with just 3.5 inches in length.
- Accurate readings on the LED display.
- Affordable.
- Reliable thermostat to maintain a precise temperature.
- Adjustable temperature control.
- The temperature controller is outside of the water â no wet hands.
- Stylish in design and visually appealing.
Cons
- The power cord is short.
- No automatic turn-off feature when it is out of the water.
Hygger Submersible Heater
- đ ăCompact Small Heateră110-120V/60HZ oval shape design little aquarium heater, fast heating for small fish tank....
- đ ăExternal Controllerăeasy to set the temp on the controller, only show farenheit temp, you can set the temp...
- đ ăDigital Displayăwith led display on the midle of the heater front side, when the fish tank heater is heating,...
- đ ăReliable Thermostatăthis an automatic aquarium thermostat, after finishing the temp setting, you can be...
- đ ăShut off When Out of Waterăplease note that this a fully submersible aquarium heater for fresh water and...
The Hygger Submersible Heater is a small, compact, and powerful submersible aquarium heater with memory function if power failure happens. Whereas, with its built-in thermometer, you can monitor water temperature in the tank!
The protective plastic cage gives it a cool look. The temperature controller is outside the tank on the cord, which is pretty convenient.
The suction cups seem reliable and havenât moved since I set them. Two strong suction cups can be placed anywhere in the tank and replaced quickly.
What else I like about Hyggerâs heater is that it has its own protection to stop working when the water isnât fully submerged. This type of safety feature isnât usually found at this price point, so kudos to them for providing it!
I think the Hyggerâs Submersible Aquarium Heater is a great addition to small tanks with water volume between 1 and 13 gallons. Itâs affordable, compact, and allows you plenty of space for your fish!
Pros
- 50-watt and 100-watt are both 4.5 inches in length.
- Very affordable and reliable.
- Auto shut-off feature when the preset temperature is reached.
- Auto shut-off when the heater is below the water level.
- It will also automatically shut off if the temperature is above 95 F.
Cons
- No warranty is provided.
- Sometimes the LED display may show wrong reading by 1 F.
Tetra HT Submersible Heater
- All Tetra HT heaters have indicator lights to let you know when the heater is on. It will be red when heating and green...
- The HT10 uses a built in electronic theromstat to automatically maintain water at 78° F which is ideal for most...
- Ideal for aquariums between 2 to 10 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...
- Please read all label information upon delivery. DO NOT plug heater into an electrical outlet until it is placed inside...
The Tetra HT10 submersible heater is a 5.25âł long compact and durable heater that can be used with aquariums up to 10 gallons. This handy little device will help keep your fish happy.
The Tetra HT Submersible Aquarium Heater is perfect for small to medium fish tanks. It features an automatic thermostat that keeps water at 78° F, suitable for most tropical species of freshwater creatures!
Make sure you purchase one made for whatever tank size is being heated. The wrong size can cause underheating! Also, you should cover your tank with a hood or glass canopy to contain the heat inside the aquarium.
The red light will come on when the heater is heating up and turn off when the proper water temperature is reached, and the green light comes on.
The Tetra HT Submersible Heater is a fully submersible heater for aquariums. This heater can be installed vertically or horizontally, and its small footprint makes it easy to conceal behind plants or other décors.
Pros
- Reliable heater for up to 10-gallon tanks.
- Very affordable.
- Easy to use for new users.
- The Red and Green indicator light is convenient.
- It can be installed vertically or horizontally.
Cons
- It is not an adjustable heater.
- No dry run protection feature.
Hydor Slim Heater For Aquariums
- The Slim heater will increase the water temperature of mini aquariums up to 10 gallons by a few degrees compared to the...
- Extra small slim fish tank heater 150 is a great choice for Betta fish and for fish tanks 5 to 10 gallons, measures 6.1L...
- Heater can easily be placed submerged in water or even under the tank gravel; The 90 degree angle makes this great for...
- Plug & play universal fish tank heater, the slim fish tank heater can be used in both fresh or saltwater environments
- Easy to hide fish tank heater is ideal to use for betta fish, gold fish and glow fish
The Hydor Slim Heater is a plug-and-play aquarium heater that can be positioned under gravel. The Slim Heater is a safe and economical choice for your fish tank.
The 15-watt heater is only 6.5 inches long and perfect for aquariums between 5 â 10 gallons in size.
It has no glass components, so there is no risk of sudden damage if it accidentally falls off your hands.
Hydorâs Slim Heaters will help you keep your fish healthy by promoting the ideal water temperature. It has an adjustable temperature dial to ensure your fish have the perfect water temperature.
It is specially designed with an innovative positive thermal coefficient element, which ensures that it warms up to 5-10 degrees warmer than room temperature!
Pros
- Convenient for fish bowls and Betta fish tanks.
- Very effortless to use, only plug-and-play.
- This heater can be positioned under-gravel also.
- No glass component, so not fragile.
Cons
- Minimal power, maximum of 15 watts.
- Not suitable for freezing winters.
- No temperature adjustment option.
Aqueon Preset Aquarium Heater
- Preset to 78 degree, accurate to plus/- 1 degree
- 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
When it comes to fish tanks, Aqueon has everything. With innovative products and prices that canât be beaten â they are one of the best places for any aquarium enthusiast!
With a preset temperature of 78° Fahrenheit (25 Celsius), this aquarium heater provides perfect conditions for most tropical fish species and other animals like turtles or invertebrates.
This product features state-of-art technology with safety measures built into every design, ensuring no worries about overheating. In addition, it has an easy-to-use thermostat that shuts off at higher temperatures, so your pets stay happy in their home!
The Aqueon Aquarium Heater is an excellent choice for any small aquarium with a black background. This heater will fit in perfectly and be almost invisible, which means you can enjoy your fish without worrying about the aquariumâs look being unpleasant!
The price tag also makes this product very affordable â perfect if cost efficiency matters at all times (which it does)!
Pros
- Comes with a 1-Year warranty.
- Affordable aquarium heater.
- Automatic shut-off feature when the preset temperature is reached.
- Built with shatterproof material.
- You can place it either horizontally or vertically in your tank.
Cons
- Non-adjustable temperature.
- No indication of the current temperature in the tank.
Hitop Adjustable Aquarium Heater
- Explosion Proof: The aquarium heater is made of 2mm thickened quartz glass, 33% thicker than ordinary glass,...
- Application: 50W water heater is suitable for 5 â 15 gallon tank, also suitable for both saltwater and freshwater,...
- Accurate Temperature: The fish tank heater can be adjusted from 68°F to 93°F (20°C - 34°C), comes with a thermometer...
- Long Service Life: This fish heater adopts 8-slot multi-branched heating wire ceramic frame, shorter length, 7.8*1*1...
- Complete Accessories and Warranty: This aquarium submersible heater comes with accessories you need, in addition to the...
The Hitop Adjustable Aquarium Heater has three different sizes, and the 50W adjustable heater is 7.8âł long (longest in the list). It can be used in 5-20 gallon fish tanks and saltwater/freshwater tanks.
This heater is simple, beautiful in appearance, and will not destroy your fish tank landscape.
Hitop Adjustable Aquarium Heater is a high-quality & accurate heater for your aquarium. The explosion-proof glass, which is 33% thicker than usual, makes it safer for humans and animals.
It has an automatic shut-off feature, so there are no worries about overheating.
It has a thermometer sticker and is convenient to detect the water temperature without another pay. In addition, the 8-slot multi-branched heating wire ceramic frame can save more space for your fish and better heat dissipation, which can prolong the service life of this aquarium heater.
It comes with suction cups (including one extra for replacement), so you can place it anywhere you want on the glass of your aquarium. However, the heating element must be fully submerged in water to avoid burning up and damaging the unit!
Pros
- It is safe, reliable, and explosion-proof.
- Good in maintaining temperature.
- Suitable for freshwater and saltwater.
- Simple and beautiful in appearance.
- Automatic shut off when the preset temperature is reached.
Cons
- This heater is relatively larger â almost 8 inches!
Small Aquarium Heaters: A Few Tips
Get One Back Up Heater
You can never be too careful with aquariums. So itâs always a good idea to have one backup heater just in case your main unit malfunctions or stops working altogether, and you want it so that when this does happen, there will still probably not be any problems!
If you want to keep your fish healthy and happy, the water must stay at a consistent temperature. A backup heater will also ensure no fluctuation occurs when other unit struggles.
Get More Watt If The Average Temperature Is Low In Your Home
Heaters vary in power and size, so it is vital to research what wattage you need for your aquarium. For a 10 gallon tank, I recommend at least 50 Watts.
If thereâs no cold winter, a 50-watt heater will do just fine in a 15-gallon tank also. But if it gets freezing, get at least that much power to keep your fish warm and comfortable!
When winter comes, make sure you have an effective way to keep your fish warm. An undersized aquarium heater is not capable of heating an entire tank, and fish may get sick if itâs too cold outside!
The Heater Should Be Realistically Durable
While it may seem like the dream of owning an aquarium heater is to have one that lasts forever, this reality doesnât unfold as we hope.
The best indicator for durability in fish tank heaters comes from their provided warranty period â how long they can take care of your needs in case of any significant issues with functionality.
The warranty on your new small heater will ensure that you have peace of mind, knowing the company is confident in its product. Remember that more extended warranties mean a lower risk for failure, so make sure to buy one with at least 1 year worth!
Final Words
When it comes to small aquariums, many factors can affect the temperature. And with so many heaters on the market, itâs not always easy to find one for your tank size.
To help you out, Iâve compiled a list of six top-rated small aquarium heaters above and reviewed them with pros and cons! Hopefully, it helped you.
If you want more information about any of these products or if you have anything else to ask me, please leave a comment below this article, and Iâll get back to you as soon as possible. Thanks again for reading my blog post today.
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