Eheim is a well-known brand in the European market, and the Jager 50-watt represents one of eight sizes in their submersible heater series. The unit should be mounted horizontally in order to take advantage of the automatic shut-off safety features. It can be recalibrated and features an indicator light. The housing is made from shatterproof glass.
This heater features an automatic low water level shut-off for protection.
An indicator light activates when the heater is actively working.
This product comes with a three-year manufacturer backed guarantee on parts.
This unit’s body is long, which may limit its placement within the fish tank.
As a German import, customer service and replacement may take longer than other brands.
The Aqueon Pro Adjustable Heater is our favorite choice as it offers the best balance of price, features, and functions.
The 100-Watt Pro Adjustable is one of five heater sizes available in this line from Aqueon. The plastic materials used for the heater body are designed to prevent shattering from continuous heating and cooling. A large blue knob located on the top of the unit is able to adjust the temperature settings within one degree. The indicator light operates continuously, indicating electrical power and status.
The manufacturer offers a limited lifetime warranty on this heater.
An electronic thermometer provides accurate temperature readings within one degree.
The plastic used near the heating element weakens the overall durability of the device.
The company is based in the United States, but contact and service can be hit or miss.
The Original Theo is the smallest in this heater line from Hydor. The control knob is marked in one-degree increments and can be accurately set after some adjustments. The length of the heater body is short enough to fit into tanks as small as 2.5-gallons. Its body is shatterproof and shock resistant, and an indicator light allows users to know when the heater is on.
This heater can be mounted horizontally or vertically within the fish tank.
The seven-inch length is ideal for fish tanks less than 10-gallons in size.
The built-in thermometer is not as sensitive as it could be for smaller tanks.
The control knob is sensitive and may take multiple adjustments to set properly.
This offering from Fluval is the largest of three in this line of heaters. The LCD display can read both Celcius and Fahrenheit. It provides a temperature range between 68 and 93-degrees. While the heater can be mounted in various positions, the manufacturer suggests that it should not be installed horizontally, and it comes with a five-year warranty.
The LCD display is clear and easy to read when the device is mounted.
This heater includes two temperature sensors that provide accurate readings.
Its design incorporates a fish guard that helps to prevent fish from making contact.
The user must follow the directions carefully as the set-up is complex.
A horizontal installation within the tank will void the manufacturer warranty.
This product comes in a very modern and sleek design with a body that is only 1/3-inch thick. A side-dial is placed near the top of the heater and multiple lights indicate the temperature settings along the dial. Thermal protection and a shatterproof covering are backed by a three-year warranty by Cobalt Aquatics.
The flat design can provide more mounting options and may easier to disguise.
This heater can be set within 0.5-degrees for a very precise temperature.
The Neo-Therm comes with a three-year manufacturer warranty for this product.
This heater’s controls are sensitive and may require multiple attempts to set.
The suction cups that are provided could be improved upon.
This external device is one of three models in Hydor’s in-line series. The manufacturer recommends that the unit should be mounted in a vertical position. It can be used with freshwater or saltwater fish tanks. The PTC technology helps to safeguard against overheating the aquarium’s water.
As an in-line heater, this product will work with a wide variety of aquariums.
It connects to a 5/8-inch hose that should not restrict water flow.
The temperature settings are precise partially due to water flowing through the heater.
This device must be mounted to the outflow hose and might be inconveniently located.
Due to its location, monitoring the device can be more difficult than with other types.
This model represents one of two devices available from Tetra. The company has a well-established name within the hobby and is known for simply designed products. It has been designed to take up minimal room within the tank and can be disguised easily. The heater has been pre-set to maintain a water temperature of 78-degrees. A set of green and red lights allow the user to know when the heater is active or passive.
This device can be mounted in either the horizontal or vertical positions.
The heater is small in size which makes it easier to hide inside of the tank.
The temperature range on this heater is pre-set and cannot be adjusted.
The lack of adjustability will require closer aquarium temperature monitoring.
The 500-watt model is one of six sizes offered by ISTA for the North Amerian market. The product is UL listed and has been offered with US styled house plugs for the last several years. The digital readout is easy to read with red numbers and the adaptors can connect to a 5/8-inch hose. While the temperature range is accurate within 2.5-degrees, it does come at an extremely competitive price.
The heater comes at a low price point for the wattage rating.
This Asian product now comes with American-style plugs and no longer require an adaptor.
This external heater must be used in the vertical position.
The heater comes with limited information and illustrations in the directions.
This device provides a guard that keeps most fish away from the heater’s surface while allowing adequate water flow around the heating element. The quartz glass is high quality and provides protection against shattering and explosions. The LED provides a thermometer reading for the water near the device and can be used in both freshwater and saltwater aquariums. The temperature range is between 68 and 93-degrees.
A protective sleeve helps to keep fish away from the heater surface.
The LED display offers large numbers that are easy to read.
This heater features a shatter-proof housing that is also explosion proof.
The digital numbers are extremely bright and can stand-out in the fish tank.
The product lacks overheating protection and may require more monitoring.
This hanging heater measures over 14-inches, but is only one-inch thick. The unit is made from durable metal and heats the water column quickly, with a temperature range between 70 and 92-degrees. The manufacturer offers a model with a heater guard which can protect your fish from touching the hot surface. The analog controller is easy to operate and can be placed around the tank exterior.
The titanium housing can heat the water column more quickly than other materials.
The metal body is highly durable and should last for a long time.
The controller is located outside of the tank, allowing a user to stay dry.
The temperature range varies by up to two-degrees, providing a less-accurate reading.
Its metal surface retains heat for a longer period of time and is not shielded.
Buyer’s Guide: 20 Common Aquarium Heater Questions
Do You Really Need an Aquarium Heater?
Many people who have fish in their house don’t keep aquarium heaters.
Not everyone needs an aquarium heater if we are being honest.
But some reasons warrant that you use an aquarium thermometer.
For example, if you live in an area with a generally cold climate, your fish tank will be the same temperature as the outside environment.
Not all types of house fish can survive in such a cold climate.
Other than that, aquarium heaters are also great for winters.
Some fish like Betta need exceptionally warm surroundings to flourish.
Many other tropical fish have the same demands.
There are yet more reasons why you should have an aquarium heater in your fish tank.
Warm water will prevent your fish from getting sick.
Sometimes you will notice that your fish immediately becomes more upbeat when you switch the heater on.
Many fish will also prefer to stay close to the heater since that is where they will feel the most comfortable!
The fish that prefer warm water also releases “happy bubbles” when the environment is to their liking.
Other than all of this, aquarium heaters also help in breeding fish.
Many types of fish need a specific temperature to spawn.
Naturally, that is where your aquarium heater steps in.
This is why aquarium heaters are highly useful.
In fact, an aquarium heater is one such piece of equipment that will help separate a good fish owner to a lousy fish owner.
In case you need to be convinced further:
An aquarium heater hardly costs much, especially if it is for domestic use.
Most of these heaters have automatic features that prevent the water from overheating.
Many heaters also come with other extra features that make your fish as happy as can be.
Clearly, you won’t even have to fret about maintenance all that much.
So why not invest in it and let your fish live long and happy?
We have a list of incredible aquarium heaters, and any one of them might be useful to you.
Understanding a bit about the equipment used to heat a fish tank is important when deciding what the best aquarium heaters are for your tank.
1. What Are Aquarium Heaters Made Out Of?
Many heaters are made from glass tubing, with some being filled with sand. Other styles can be made of a combination of metals and plastics. There are also aquarium heaters that consist of metal cables covered in a rubber sheath.
2. What Types Of Aquarium Heaters Are There?
Cable Heating System: With this type of heater, a cable is placed under the substrate and is connected to a controller. Aquarium enthusiasts who keep plants in freshwater tanks use these as they help to eliminate dead spots.
Hanging Heaters: This type of device can be used for basic heating requirements. They are only partially submerged and are not as efficient as a fully submerged unit.
In-Line Heaters: These units are located outside of the fish tank. Some devices will connect to the filter hose. Other in-line heaters are positioned in the aquarium filter itself.
Submerged Heaters: Submersible heaters are placed in the aquarium. They are often attached to the tank wall by suction cups.
3. How Does A Submersible Aquarium Heater Work?
A submersible heater is a device that contains a heating element that radiates heat through the housing to heat the surrounding water. A thermometer on the device detects the water temperature and turns the heating element on and off to achieve the proper temperature. Most devices use a controller to set the desired temperature range.
4. Can You Shield Fish From Direct Contact With Heaters?
Yes, you can. Many submersible heaters come with a shield or guard. This add-on helps to prevent fish from touching the glass tube or heater body. It is also designed to allow proper water flow around the heater.
Many manufacturers highlight this safety feature on their products, and they can be purchased separately for heaters that do not have a guard.
5. Can You Use Heating Mats To Heat An Aquarium?
Some aquarium keepers have used heating mats to help to heat their tanks. The mat is placed below the tank. This type of heating is not very accurate or efficient. The aquarium glass and plastics conduct heat poorly. Also, the added layer of substrate cuts into a mats ability to heat the water column.
6. How Does An Undergravel Heater Work?
An under gravel heater uses a cable or cord to heat the water column. The cable is placed under the substrate, spaced evenly to provide the best coverage. The cable is connected to a controller that monitors water temperature and sets the desired temperature range. They are often used in planted freshwater tanks as well as aquariums capable of holding large volumes of water.
7. Can You Use A Cable Heater In A Saltwater Tank?
A cable heater should not be used in saltwater aquariums. If the cable ever needs service or requires replacement, it must be pulled from under the substrate. This will destroy saltwater plants and reefs that have been established in the tank.
8. What Style Is The Best Saltwater Aquarium Heater?
Many fish keepers feel that submersible heaters are the best type of heaters to use with saltwater tanks. They are easier to access than cable heaters are. These heaters require less maintenance and monitoring than hanging heaters. A submersible heater is more mobile and can be placed nearly anywhere within the water column.
9. What Is The Best Small Aquarium Heater?
Many submersible heaters are available for fish tanks that are 10-gallons or less in size. A major feature to look for is size. Small tanks are limited in room, and regularly sized aquarium heaters may take up too much space. Another consideration should be wattage, which determines how many gallons of water the heater can effectively warm up without being overworked.
10. How Are Aquarium Heaters Measured For Power?
All devices used to heat the water column in a fish tank are rated by their wattage. The wattage determines how much energy the heating element can generate. Higher wattage ratings will heat a fish tank more quickly. The higher rating will also heat larger volumes of water.
Manufacturers will list the wattage of the device on the product package or in its online description. They will also indicate a general range of tank size, in gallons, that the heater should be paired with.
11. Does Room Temperature Influence Heater Requirements?
Yes, it does. Cooler rooms will require that the aquarium heater operate more often and for longer periods of time. Conversely, a room with a warmer average temperature will need the aquarium heater to work less. The average room temperature is factored in when determining the wattage requirements for a fish tank.
12. Is There A Formula That Can Be Used To Determine The Wattage Needed?
Most hobbyists calculate that each gallon of water will require between 2.5 and 5-watts of power. There are many calculators and charts available online that can help determine the wattage as well. These systems take the average room temperature and subtract it from the temperature that you desire the aquarium to maintain. They will then determine the required wattage based on this difference and the tank size.
Many fish keepers, especially novices, will use the product’s listed rating. If a heater is near the limits of its power, it is always advisable to step up to the next wattage size.
13. Why Do Some Tanks Use More Than One Heater?
On larger tanks, aquarium owners will often use two smaller heaters instead of one large heater. Using multiple devices allows them to heat the water column evenly and more quickly. Also, the extra heaters can prevent the water from becoming too cool should one of the devices break down.
14. Do all fish require heated water?
Some fish are capable of surviving in cooler water, and there are species that actually require lower temperatures in order to thrive. Before purchasing a heater, you will want to determine what type of fish you plan to keep. Researching the different species will determine water temperature requirements. Many popular tropical fish species prefer water that ranges between 76 and 80-degrees Fahrenheit.
15. How Long Should A heater Be left On?
Aquarium heaters are designed to be left on continuously once they are plugged in. The unit is equipped with a thermometer that monitors the water’s temperature. When the water dips below the set range the heating element is activated. Once the water reaches the set range the element is turned off.
16. How Can You Tell When A heater Is On?
Most aquarium heaters feature lights that come on and off depending upon the heater’s current status. Some indicators make use of colored LEDs to indicate the unit’s activity. Some basic designs do not have indicators but require the user to observe the element itself to determine what state the heater is currently in.
17. Is It Dangerous To Use A High Wattage Heater On A Small Fish Tank?
It is possible to use a heater designed for larger tanks on a smaller aquarium. There is, however, a potential danger in doing so. There is a chance that the larger heater may overheat the water, which can be deadly for the fish.
18. How Do You Adjust The Temperature On An Aquarium Heater?
Most heaters will come with a knob or control box that allows the user to adjust the output of the heating element. Some units provide a simple control with no markings while others list temperature increments. There are basic models that cannot be adjusted but are set at a predetermined range.
19. What Is The Best Location For A Submersible Heater?
These devices should be placed along the back of the tank, near the water flow generated by the aquarium filter. This prevents them from blocking the view and helps to circulate the heated water evenly and quickly.
20. How Do You Monitor The Temperature In The Aquarium?
A separate thermometer is placed in the tank at a location that allows you to observe temperature readings. In larger tanks, multiple thermometers can be placed to keep tabs on the water column. These devices should be placed far enough away from the heater that it will not cause false readings.
What to Look for When Buying an Aquarium Heater?
When buying an aquarium heater, you need to, of course, set a budget.
Aquarium heaters don’t exactly cost a lot generally.
You can get a fairly sturdy one that lasts a while for a very reasonable price.
This is why it is in your best interests to get a good one on your first try.
Don’t get testy with cheaper brands since they can prove to be quite fickle.
Of course, there is a vast difference in price between heaters used for domestic purposes, and those used industrially.
But you’re looking for a high-quality domestic one, and you can easily find one for a couple of bucks.
Aquarium heaters come in a vast range of power ratings.
On average, an aquarium heater can go from 25W to 300W easily.
Naturally, the higher the power rating, the larger the tank the heater can power.
Most aquarium heater brands have multiple options in their heaters so that they can power a wide range of tank sizes.
They offer a size chart as well, showing you how large a tank one can power.
In case you don’t know the capacity of your tank, you should measure it before you go looking for an aquarium heater.
If you buy a high wattage heater for a small tank, it will overheat the tank even at the lowest setting.
If you buy a low wattage heater for a large tank, it will never be able to heat up the tank on its own evenly.
The material of the tank it is used for
You should know that not all types of heaters are used for all kinds of tanks.
Most heaters in the market are used explicitly for glass tanks and aquariums.
If you have a plastic tank, you have limited your options of an aquarium heater by a large margin.
This is because:
The heat from the aquarium heater can distort or melt the plastic walls of the aquarium heater.
This is why you need to look for a heater that offers protection from plastic distortion.
Other than that, you can also place protection around the walls of your plastic aquarium to prevent it from losing its shape.
This goes for any tank material other than glass.
Always know if the heater you are planning to buy will work for your tank or not.
Every aquarium heater available in the market has a specific temperature range.
Every fish you can keep in your house also thrives in a specific temperature range.
So make sure that the aquarium heater you buy covers that specific temperature range.
Check whether it is Submersible
Most aquarium heaters available in the market need to be fully submerged in the water to work perfectly.
Now, if you have an aquarium or a tank that is too small height-wise, the heater will not be able to work properly.
So keep in mind the height of your tank and the dimensions of the thermometer when you are buying one.
You can look for an aquarium heater that does not need to be fully submerged to work properly.
Of course, you can also lay it flat on the aquarium floor or at an angle to make it work properly.
Many aquarium heaters come with additional features as well.
These include extra thermometers, external controllers, adjustable knobs, etc.
You can pick out an aquarium heater based on these external features if any of them suit your needs.
Tips on Using an Aquarium Heater
First and foremost, you need to keep in mind that the thermostat temperature on the heater is nearly always different from the room temperature. This temperature depends on the temperature in the outside environment. This is why you always need a separate thermometer to monitor the water temperature carefully, so it doesn’t go overboard.
Always check for dangerous openings on the heater. These openings can trap small fish and prove to be fatal to them. If you find any such openings, try to seal them before you place the heater in the tank.
Try to increase the temperature in your fish tank gradually.Your fish can run the risk of getting shocked or falling sick if you immediately increase the water’s temperature.So get them used to a small increase every day before you bring them to the desired temperature.
If you find that the aquarium thermometer does not fully submerge vertically in your tank, you can try placing it horizontally or at an angle.Of course, do not try this if the manufacturer has specified that the heater should stand vertically.
Also, keep in mind that your heater should be fully submerged in the water at all times. If the heater runs dry, it can get damaged.It can also get damaged if it runs when partially underwater.Some aquarium heaters have sensors that ring alarms or flashlights when this happens. But if your heater does not have this feature, then you should keep a keen eye on it at all times.
More Top Rated Fish Tank Heaters
Mylivell Aquarium Heater Submersible Auto Thermostat Heater