5 Best Small Aquarium Heater Brands (1 to 10 Gallon Fish Tanks)

If you’re thinking of setting up a small fish tank or bowl, say, one that is 10 gallons or less, you might not think too much about getting a heater. Do you need one in such a small tank? What’s the worst that can happen?

Before you set up any tank or bowl, planning is essential. Do you need a heater in a small aquarium? It depends.

What determines whether or not your tank needs a heater is not the size of it, but what kind of fish you’re planning to keep. Some fish prefer cooler water and can get by without a heater. Some of them include fancy goldfish, white cloud mountain minnows, and some loaches, tetras, and barbs, but the truth is that none of these do particularly well in a small tank anyway.

The smaller your tank is, the more limited you are to the fish you can keep in it. Shrimp, snails, and bettas are your best bets, but make sure you do your research before adding anything. Putting a fish that needs at least 20 gallons into a five-gallon tank is not only cruel, but it will also not end well. For example, a lot of people think keeping a goldfish in a small bowl is fine, but the truth is that goldfish need at least 20 gallons to be safe, healthy, and happy.

Once you research the fish you’re planning to keep in your nano tank, you’ll soon realize that a heater is a good idea. Because it’s not always easy to find a reliable heater for a small tank, we’re going to take a look at five of the top aquarium brands and the heaters that are suitable for tanks between one and ten gallons. Hopefully, this will make it easier for you to find a heater that works for your setup.

Cobalt Aquatics

Our first heated brand is Cobalt Aquatics, which has been around since 2011. It’s led by a team with more than 60 years of combined experience in the aquatic industry, including a former research biologist, a high-end African cichlid importer, and one of the founding members of Marineland Aquarium products. They decided to start a company of their own, taking the lessons their mentors had taught them and combining it with their years of experience in fishkeeping.

This brand started out making a line of probiotic-enhanced flake fish food and quickly expanded into other foods, lighting, and equipment, including some of the best heaters available for small tanks.

Cobalt Aquatics Flat Neo-Therm Heater

What makes the Cobalt Aquatics Flat Neo-Therm Heater such a great choice? It’s available in a wide range of sizes, including a 25W option that’s perfect for tanks up to six gallons and a 50W for tanks as large as 12 gallons. Finding a heater for a small tank – especially one smaller than six gallons – is not always easy. Finding one with as many features as this one is almost unheard of.

This heater has a super-flat design, which is absolutely essential for micro tanks. Small tanks do not have a lot of space, so finding a heater that doesn’t take up too much room is key. Installation is simple. A reversible mounting bracket with suction cups is included so you can position it anywhere.

A lot of heaters designed for small tanks have one preset temperature, but one of the things that makes this Cobalt Aquatics heater so special is that you can adjust the temperature between 66 and 96 degrees F. Plus, it has integrated thermal protection so you don’t have to worry about it overheating above the set temperature.

It’s also extremely effective. It’s not always easy to maintain the temperature of an aquarium that’s much warmer than room temperature. Most are only able to raise the water temperature by one or two degrees. The Cobalt Aquatics heater can raise the temperature of the water 11 degrees above ambient temperature. Now, this isn’t necessarily something that you would need to do, but the fact that the heater is powerful enough to do it means that it will have no problem maintaining a standard temperature. Plus, it shows how well-made these filters are. You do not have to worry about overworking them.

Another great thing about this small aquarium heater is that it’s practically indestructible. It’s made of resin and thermoplastic and has a shatter-proof outer-casing that’s so strong, the heater is backed by a three-year warranty.

 Mini-Therm model

If you’re looking for something smaller, Cobalt Aquatics also has a Mini-Therm model that is specially made for small aquariums. They have a 5W for tanks up to 1.2 gallons, 10W for up to 2.4 gallons, 15W for up to 3.6 gallons, and 20W for up to 4.8 gallons. This model is a little different than the Flat Neo-Therm Heater. The casing is made from shatter-proof plastic polymer and the internal ceramic disc provides even heat distribution for the tiniest of tanks.


Another great brand to consider when shopping for a small aquarium heater is Aquatop. This company was started by a group of aquarium enthusiasts with over 35 years of experience in the industry. What’s great about this brand is that they really love the hobby. The founders have been into aquariums since they were kids and want to make everything as simple and effective as possible so that everyone enjoys the hobby as much as they do.

In addition to selling aquarium heaters and just about any other equipment you need to keep your tank up and running, the Aquatop team has also created an in-depth learning center and blog on their website where you can learn about different types of fish, how to solve some of the most common aquarium problems, and get updates about what’s next for the brand.

Aquatop has a variety of aquarium heaters, ranging from simple analog models to more advanced titanium designs.

Nano Aquarium Digital Heater NH

The Nano Aquarium Digital Heater NH is only 25W and meant for tanks between four and seven gallons. It has an insanely compact design that makes it really easy to fit into these small tanks. Each unit has a built-in electronic thermostat that comes preset to 78 degrees F that’s accurate to within 1.8 degrees. You don’t have to worry about turning it off and on or adjusting any settings. When the water reaches the set temperature, the heat turns off automatically to prevent overheating. Suction cups are attached for quick and easy installation. This small heater is made of reinforced plastic and is practically unbreakable when used appropriately.

Nano Aquarium Digital Heater D1HT

For bigger tanks between five and 20 gallons, Aquatop has the Nano Aquarium Digital Heater D1HT. The cylindrical shape is 10.5 inches long with a 1.25-inch diameter. Since it’s very thin, it’s not too intrusive in your tank, but the length might make it a tough fit for tanks on the small end of the range.

This heater has a clear digital temperature display and an easy-to-use control button. While most heaters have a built-in temperature sensor, this one is attached separately and can be placed anywhere in your tank. You can use this thermometer with a saltwater or freshwater aquarium and it saves energy when compared to analog heaters.


Another well-known brand you can count on when it comes to heaters for a small aquarium is Fluval. This brand has been in the business since 1975 when they developed the world’s first three-stage filtration system with synchronous motor technology. It was a breakthrough that’s still being used today. Since then, this pioneering brand has continued to grow, making products that raise the bar for functionality and quality.

Fluval is also very involved in charitable and educational efforts across the fishkeeping community but shining a light on endangered fish species and funding the protection of wild coral reefs. This is a well-rounded company that strives to help hobbyists setup and maintain beautiful aquariums while raising awareness about environmental and aquatic issues.

10W for tanks up to three gallons and 25W for tanks up to six gallons

There are three types of Fluval heaters that are suitable for small tanks. First is the Submersible Aquarium Heater, which is available in 10W for tanks up to three gallons and 25W for tanks up to six gallons. This design features a shatterproof polymer construction that’s safe and protects both the heater itself and the inhabitants of your tank from damage. The fully submersible design is safe for freshwater and saltwater, and each one is preset to a temperature ranging between 76 and 78 degrees F so you don’t have to make any adjustments. It turns off when the water reaches the appropriate temperature and there’s a small LED light that alerts you when the product is in use.

The 10W heater is only 5.3 by 0.78 inches and the 25W is 5.9 by 1.1 inches, both small enough to fit nicely into smaller tanks. They have a sleek black design that shouldn’t be too difficult to hide but isn’t particularly distracting so it shouldn’t take away from the environment you’re creating in your tank.

E Series

A good choice for tanks between six and 10 gallons is the E Series. This submersible heater features an internal thermal sensor which makes it super accurate. It has an LCD display that can show temperatures in either Celsius or Fahrenheit. Setting the temperature is easy, and you can choose between 68 and 93 degrees F in 0.5-degree increments. This gives you precise control over the temperature so you can make any necessary adjustments.

Something cool about this one is that the temperature display changes color if the water temperature varies more than two degrees from the selected temperature setting. If the difference is more than 5.5 degrees, the screen flashes to alert you to the problem.

The E Series also features an integrated fish guard that prevents fish and other living things in your tank from coming into direct contact with the heater core. There’s also a protective glass sleeve that protects larger fish from shocks.

Installation is really easy. A slim-profile mounting bracket is included, and you can adjust the positioning without actually having to remove the bracket. This lets you mount it at different angles to fit it among your tank’s décor while still being able to see the LCD screen.

There are no moving parts to this heater and nothing to corrode or wear. In fact, it’s so durable, it’s covered with a five-year warranty.


Finally, Fluval also offers the M-Series in a 50W size that’s good for tanks closer to 10 gallons. This one is a little basic compared to the other Fluval options, but some people prefer the simple, straightforward design. The durable, mirror finish blends into the tank’s surroundings by reflecting what’s around it and is particularly easy to hide behind aquarium plants. The control is easy to adjust, and large suction cups make installation easy. This heater is 11 inches long and has a one-inch diameter, so it’s long but generally easy to hide. One word of caution, make sure you follow the directions carefully when installing this one. They suggest letting it acclimate to the tank temperature before plugging it in and it has to be completely submerged to prevent damage.

Penn Plax

One of the interesting things about Penn Plax is that they don’t just know about aquariums. They’re passionate about all kinds of pets. The brand started as a small family-owned pet shop in Brooklyn in 1956 and, more than 60 years and three generations later, became one of the most well-respected pet brands on the market.

Innovation has always been the core of Penn Plax. As the Goldman brothers’ pet shop grew more and more popular, they began developing new products for their customers right there in the shop. Among other things, Penn Plax invented the first 3D aquarium background, developed their own aquarium filter, and devised a way to create underwater rivers. By the 1960s, the Goldmans were ready to expand into a large-scale manufacturing facility and the Penn Plax brand was born.

Penn Plax has a few small aquarium heaters to choose from, and, as you can see from their extensive product catalog, there are plenty of other pet products available, too.

One of their most popular small heaters is a part of their Cascade Heat line. This 25W heater is perfect for tanks up to five gallons, and the 50W is the right size for tanks from six to 10 gallons. The Cascade Heat Aquarium Heaters are fully submersible and are accurate within one degree of the set temperature. The easy-to-read gauge displays temperatures in both Celsius and Fahrenheit. It comes preset to 76 degrees F but you can easily program it to any temperature between 68 and 89 degrees. All you have to do is dial in your preferred temperature, attach it to the tank, plug it in, and you’re ready to go. The heater automatically turns on and off as needed to maintain the set temperature, and the Easy View indicator light lets you know when it’s on and when it’s not.

The Cascade Heat line is so effective because it uses superior insulation and has excellent heat distribution from end to end, so it heats your water more reliably. The shock-resistant glass keeps your fish safe and extends the life of the product.


This heater can be

This heater can be installed either horizontally or vertically using the included dual-mounting suction cups. The 25W model is six inches long and the 50W is seven, so either size is easy enough to hide and doesn’t take up too much room. All Penn Plax products are made to last and covered by a three-year warranty.

Another option is the Cascade Mini. This is a small, simple heater that’s only 10W and ideal for nano tanks between two and five gallons. It’s fully submersible and it’s important to note that it has to be completely underwater or it will no longer work thanks to an automatic safety feature that cuts power to the heater once it is exposed to air. Because of this, it’s very important to follow the installation instructions carefully. They’re not difficult, but there are a number of steps you have to take to make sure the heater adjusts to the tank environment properly so be sure to pay close attention.

This heater has a preset temperature of 77 degrees F and can be used with either a glass or plastic tank. It’s extremely small at only four inches long, and the attached suction cups make it easy to install anywhere in your tank. You can position it horizontally or vertically, depending on how you have your tank set up and which works best for your decor.


Hydor is a really interesting brand that is heavily focused on technology and engineering. It was founded in 1984 by an engineer and his wife who saw a need in the aquarium market in the United States. They started with a range of hang-on filters and rapidly grew, creating many innovative products including pumps and heaters.

Today, Hydor has shifted its focus to solidifying its brand by becoming the benchmark for design and innovation in the aquarium industry. Their products are sold worldwide and are well known for being high-performing and innovative. While this might sound like the focus on larger, more elaborate equipment for complicated setups, Hydor has created plenty of amazing options for small tanks. Their small heaters are some of the simplest and most reliable on the market.

The Hydor Submersible Glass Aquarium Heater is available in 25W for tanks from two to seven gallons and 50W for tanks between five and 14 gallons. This is billed as the first shatter-proof heater and is shock resistant and exceptionally durable.

These heaters are about seven or eight inches long and you can position them horizontally or vertically using the included suction cups. Each has a graduated scale and a simple top dial to choose the temperature setting.

Something that really stands out about this design is that it has a special feature where it won’t get damaged if it runs dry. Considering a small tank heater typically breaks if it’s exposed to air, this is a pretty cool feature that might come in really handy.

Another cool productAnother cool product from Hydor is this Slim Heater. It’s available in three sizes: 4W for tanks and bowls up to 2.5 gallons, 7.5W for up to five gallons, or 15W for up to 10 gallons. This heater model is small and flat, perfect to warm the water in a small tank without taking up too much room. The aquarium heater can even be positioned under the gravel to keep it completely out of the way.

This model is either round or oval in shape, depending on the size, though both are surprisingly compact. All you have to do is plug it in and it’s ready to go. There are no glass components and it’s completely safe for your fish, and you can use the Slim Heater in glass, plastic, or acrylic tanks or bowls.

The third option from Hydor is their Mini Heater for Aquariums. It’s suitable for tanks between five and 10 gallons. Size-wise, the dimensions are a little larger than the previously discussed Slim Heater, but this one is exceptionally thin at roughly 5mm. It’s safe to use under gravel, too, so you can easily tuck it away, out of sight.

This option is also not damaged if left to run dry and is extremely durable. It raises the temperature in a five-gallon tank about five degrees and about four degrees from the ambient temperature in a 10-gallon tank.

The Right Heater for Your Small Tank

It’s easy to think that keeping a small fish tank or aquarium is easy, but the truth is that it’s sometimes more difficult than managing a large tank. There’s not a lot of water so keeping it clean and safe is really important.

Finding fish that are suitable for these small habitats isn’t always easy, either. Remember, just because a fish is small, doesn’t mean it’s healthy for it to live in a small space. Take the example of the goldfish. How many times have you seen a big, beautiful goldfish in a small bowl? They need a lot more space – 20 gallons, minimum – to thrive.

It’s important to take the time to find the right fish for a small tank, but don’t get discouraged! There are some great options out there, including betta fish and snails, some of the most beautiful and interesting creatures in any tank or freshwater aquarium.

After you choose your fish, take a look at their temperature requirements. It’s always important to check, of course, but the chances are that your new friend is going to need a heater. Luckily, there are plenty of options available from some of the best brands in the industry.

We included introductions to five of the best brands as well as the small heaters they have available not only to help you choose one, but also to give you an idea of the wide variety of products out there. If you’re looking for a brand you can be loyal to, there are those rooted in innovation to choose from as well as those that started as simple, small family-run businesses decades ago.

When it comes to heaters, there are a few styles to choose from. Which will work best for you is a matter of preference but also depends on your tank setup.

Cylindrical heaters tend to heat the water more evenly because they have a larger surface area than thin, disc-like heaters. That said, most thin heaters can be tucked under the rocks on the bottom of the tank, meaning they’re completely out of the way and won’t take up any precious space as the cylindrical ones do.

Another thing to think about is whether you want to be able to adjust the temperature or not. A lot of these small heaters come with a single preset temperature so you just put them in your tank, plug it in, and it’ll set the ideal temperature on its own. That said, there are other options available if you prefer to have a little more control. For example, if you have a fish that likes the water a little warmer, a preset heater might not be the best choice. Or, if you live in a place where it gets really cold in the winter and the ambient heat in your home drops, you might prefer a heater that has a little more power to keep your fish happy all year wrong.

As you can see, there’s a lot to think about when setting up a tank, from how to take care of the tropical fish in your large aquarium, to having the appropriate water temperature for even a small tank. Choosing the right fish tank heater is an important piece of the puzzle and a simple thing you can do to get your small aquarium off on to a swimmingly good start.

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