Best Aquarium Heaters to Buy: 2019 Reviews and Guide

best aquarium heaters

As a fish keeper, you need to be aware that fish are different from human beings in the sense that they cannot control their own body temperatures. And for this reason, it is absolutely necessary to have the best aquarium water heater together with aquarium thermometers in place to help the fish get the required stable water temperature necessary for their survival.

We have the majority of the fish we keep in our fish tanks requiring warm water for them to survive. This means that unless you stay in a place where it is warm all-year round, you need a fish tank heater to keep the water temperatures stable for the fish. But getting quality water heaters can be tedious and tiresome, especially in the face of the many fake aquarium heaters in the market today. But with concise and unbiased aquarium water heater reviews, one can be sure to get a good aquarium heater to serve his purpose. This article provides an unbiased fish tank heater review, to enable fish keepers to find the right heaters with ease.

Importance of aquarium water heater

The need for an aquarium heater is a necessity, for as long as you rear fish and the temperatures in your locality keep changing. The heater will help replicate the natural environment as well as the conditions necessary for fish survival.


With an aquarium heater, you can be able to raise or lower the temperatures of your fish tank to appropriate levels, depending on the fish species that you have.

It is particularly important to have a water heater in your fish tank as the temperature changes have an effect on your fish. In most cases, the changes bring stress to the fish, and if this stress is persistent, then it can have fatal consequences. We need to remember that large water bodies such as lakes and seas have their temperatures relatively constant.

And one needs to note that while people in some countries will be dealing with low water temperatures, in other countries, people will dealing with high temperatures and will thus need aquarium water coolers for their fish to survive.

Things to consider when buying the best aquarium water heaters

Before you invest in a water heater, it is important to know a number of things that will determine which type of aquarium heater to buy. Below are some of the things to consider;

Size of the aquarium tank

The size of the aquarium tank is an important factor when deciding on which type of heater to buy. This is because if you have a large capacity aquarium tank, and then you buy a low capacity heater, then you might not be able to achieve the results that you had envisioned in the first place. At the same time, the size of the fish tank will help you understand the number of heaters to buy. If it is big, then you might want to buy more than one heater.

Salty or fresh water?

It is also important to consider the kind of water in which you are rearing the fish. Different water heaters work differently under different conditions. There are those that will work properly even when used in salty water, while others might not work. So as you plan, be sure to first know if your water tank is salty or not, and buy an appropriate aquarium heater.

Cost of the aquarium water heater

Fish tank heaters are priced differently, depending on their unique features and characteristics. For this reason, it is important for you to go for a heater that you can afford. If you just purchase a water heater without considering the cost of purchasing as well as maintenance, then you might find it hard budgeting for other aspects of the fish tank.

And apart from the purchase and maintenance costs, you also need to factor in the cost that will be associated with the power to operate the heater. You can choose to use propane, natural gas or electricity, but then these will not just come for free. You will have to pay. So as you purchase, be sure to factor in the source of the power that will be required to make the aquarium heaters operational.

Ease of installation

While most of the fish tanks are easy to install, there are those that will need some skills when installing them. This necessitates the need to consider how easy it is to install the heater.

The fish species that you are keeping

Not every water heater works for every fish species. While you buy a heater, you will need to keep in mind the kind of fish that you have. Conduct research to find out which fish tank heater is best for your fish species.

What are the various types of aquarium heaters?

In the market today, you will find various types of water heaters. This means that you need to know these types before you visit an aquarium heater store to buy one. Below are the common types of aquarium heaters;

1.      Submersible heater

These types of heaters sit under the water. Usually, it is supposed to be placed at the inlet so that it can heat the incoming water.

The heater is made up of a coiled element which has been encased in a glass of toughened plastic tube. Also, these types of heaters have a LED light placed near them to help you know whether it is on or not. Experts say that this type of heater is better than the immersible one when it comes to keeping the fish tank at a more stable temperature.

2.      In-line aquarium heater

The inline aquarium heater is best when fitted between the sump and filter so that it can heat the water as it comes back to the fish tank. The heater is made of a plastic which is heatproof.

The inline aquarium heater is the best for those fish keepers who have large and aggressive fish that fight with equipment in the fish tank. But it is also important to note that these types of heaters are generally more expensive than any other aquarium heater type.

3.      The filter heater

This is a type of fish tank heater that comes with the filter. The filter is fitted with the heater so that as the water passed through it, it is also heated before it goes back to the tank. You can easily find this type of heaters when you buy either the canister or powder filters.

4.      Immersible aquarium heater

This type of heater is also known as a hanging aquarium heater. The name comes from the fact that the heater hangs over the top of the fish tank and sits in the water. These heaters come as a starter pack for beginners, as they are the most common water heaters for fish tanks.

It only provides basic heating, as it is not as efficient as the other aquarium heater types. They are not recommended for brackish or saltwater setups.

5.      Substrate heater

Honestly, these are not actually aquarium heaters as they are not independent. They come with other types of heaters and are in the form of wires that are then fixed onto the base of an aquarium. They were popularly used in planted tanks as the heating promotes gentle water movement that can stimulate the growth of roots. They are very expensive, thus not often used by fish keepers.

7 best aquarium heaters to buy

1.      Freesea Aquarium Fish Tank Heater

Are you looking for a compact and easy to hide heater? Then this is the best choice you have. The heater comes with an easy to read large LED display. For ease of use, the heater comes with an exterior button which is used for setting the fish tank temperature from between 59 and 94 degrees. You will also appreciate the fact that this aquarium heater comes with a whole 12-month warranty.


  • Easy to hide, thanks to its oval shape
  • Easy installation, thanks to the integrated suction cups.
  • Automatically maintains the set temperatures.
  • Easy to adjust settings using its external button
  • Easy to read the temperatures as it has a large LED display



  • The temperature control box of this type of heater is not waterproof, thus vulnerable.
  • It can only work correctly when submerged, thus cannot be removed from the fish tank.
  • Comes with a short power cord, only 3.5 feet long
  • Can only work best in a fish tank with high water circulation.


2.      Hygger Submersible Fish Tank Heater

This is also a submersible aquarium heater that is both easy to install and easy to maintain water temperatures. As a fish keeper, you actually deserve this, as it is designed to last longer than others, going well over three years.


  • Comes with a long power cord of about 5.4 feet. This makes it easy for it to reach most parts of the fish tank.
  • Has an auto shut off for easy protection from over-heating.
  • Can easily maintain fish tank temperatures at a constant value automatically
  • It has a LED indicator which can let the operator know when it is on or off.
  • It is durable.
  • Its compact design makes it easy to hide it in the aquarium
  • Works for both fresh as well as salty water tanks.
  • It is easy to install as it comes with a detachable shield and two suction cups.



  • Cannot be used in a sump or turtle tank
  • Cannot be placed under the substrate
  • Can only be installed horizontally due to its design.
  • Can only work in glass tanks, not in acrylic or plastic fish tanks




Best aquarium thermometers: Reviews &Top Picks

Best Aquarium Thermometers

Every aquarium needs a thermometer. In fact, you have a thermometer inside your aquarium right now. But is your thermometer accurate? Have you actually thought about the accuracy of your thermometer? What you need to know is that if your thermometer cannot be relied upon to give accurate results, then it is useless. But you need not to worry if you have been using an aquarium thermometer that cannot be relied upon. Look at the following most common types of best aquarium thermometers.

But before that, do you know what an aquarium thermometer is? And do you need one?

An aquarium thermometer is a tool that measures the temperature of water in an aquarium. These days, there has been an increased use of thermometers in homes as people use thermometers to adjust thermostats while some use them to check if the roast has cooked well. Some even use thermometers to check the temperature of their children. Aquarium thermometer is used to check the temperature of water in the tank. They are popularly known as fish tank thermometer.

Actually, an aquarium thermometer is a very important tool and also very essential when you own a fish tank in your home. What you need to know is that you cannot check and determine the temperature of water in an aquarium by just looking at it. Thermometers are therefore very important as it allows you to check and confirm the temperature of water in an aquarium and confirm if it is the right temperature for the fish in the aquarium. For these reasons and many others, as you buy the best aquarium pumps, you also need to ensure that you purchase the best aquarium thermometers as well.

What are the different types of thermometers in the market?

Actually, there are three different types of thermometers that are commonly used for determining the temperature of the water inside the aquarium. By reading and knowing the different types of thermometers, you will realize that some thermometers are better than others. Have a look at them.

1. Digital aquarium thermometer and probe

Digital thermometer and probe for aquariumThis type of thermometer is made up of two different parts, that is, the sensor probe that sits under the water in the fish aquarium. Its function is to check the temperature of water. Also, there is a digital display. This part remains outside the water, and its function is to display the temperature of the water in the fish tank. Its function is also to house the batteries of the thermometer.

Why is this type of thermometer split this way?

The reason why the two parts are separated is to ensure that the electrical part of the thermometer does not mix up with water. Therefore, the electrical part of the digital thermometer does not get wet. So, if you do not want a thermometer that does not permanently sit in the water, then this is the best one for you. You just add a probe to your tank when you want to check the temperature of the water in the aquarium and then remove it ones you are done. Actually, it is considered coolest, especially if you have the best digital thermometer.


•    Reading can be taken in any location with a single meter

•    Unbreakable

•    Alert feature when the temperature is out of range

•    Not impacted by ambient room temperature

•    Easy to read

•    Generally the most accurate type


•    Most expensive type

•    Most require batteries to run

Under the digital thermometer and probe, we have two types, which are as described below;

i. Fixed probe thermometer

This thermometer is often referred to as instant-read thermometer. This type of thermometer is normally identified by a meter that is directly attached to the sensor probe. When using it, you just dip the probe into the water, and you will get your results in seconds.

The good thing with this fixed probe thermometer is that it takes up a little space which allows it not to be easily noticed in your aquarium cabinet until the next time you want to know the temperature of your aquarium.  But if you have a downside fixed probe aquarium, you will have to hold it with your hands when taking the temperature reading of your aquarium or else the thermometer will sink into the water.


  • Easy to read
  • Takes up little space


  • Does not have alerts


ii. Wired probe thermometer

wired probe thermometerThis is the most advanced one. A probe is separated from the meter and connected with a cord. This allows you to permanently set up the probe inside the water while the meter is outside displaying the current temperature reading of the temperature. So, with this type of thermometer, you can continuously monitor the temperature of your water by putting it anywhere on the surface of the water. This type of thermometer is advanced that it can raise the alarm even with the slightest change in the temperature. Also, this type of thermometer does not take up much of your space in your aquarium cabinet.


  • It can be placed anywhere on the surface of the water
  • It has an alarm system
  • Does not take up much space


  • Expensive
  • Require batteries to run

While it might look like all the digital aquarium thermometers are expensive, one can get a reliable digital aquarium thermometer that is cheap.

2. Submersible aquarium thermometer

This type of thermometer lives inside the water with your fish and plants. These thermometers are designed to remain inside the water. So, anytime you want to check the temperature of water, you will have to peer inside a great hands-free way. The problem with this thermometer is that it takes up a large space in your aquarium but space won’t be a problem in large tanks.

This type of thermometer is most commonly made if glass. However, there are those thermometers that are operated by batteries which are made of plastic though they are less common.

When it comes to the price of aquarium thermometers, submersible thermometers are the cheapest. In fact, you can have this type of thermometer with just a few dollars. But you need to know that Submersible thermometers are not recommended in aquariums which have aggressive fish as they are most commonly made of glass and therefore, can break when fish hit them.


•    Inexpensive

•    They operate without batteries


•    They are hard to read

•    They are fragile

i. Floating submersible thermometer

Floating submersible thermometerAs the name of the thermometer indicates, this type of thermometer floats on the surface of the water in your aquarium. This sounds great. Isn’t it? When the thermometer floats in the water, it takes up the least space. The problem with this is that it can spin with the slightest movement of water making it impossible to read the temperature of the water as you can only read it front on.

The other problem with this type of thermometer is that the filters of the thermometer can push it around until they get stuck in one corner of the tank. Also, when you have decorations or plants on your aquarium, you can’t be able to take the reading of the thermometer easily. So, the only thing to do when you want to take the reading of this type of thermometer is to take it with your hands which is not practical.


•    Many have easily viewable “safe” zone

•    Can be placed in multiple locations

•    Inexpensive

•    Not impacted by ambient room temperature


•    Breakable

•    Less accurate than digital

•    The scale may be difficult to read

•    No alert feature

ii. Standing submersible thermometer

Standing submersible thermometerThis type of thermometer is weighed allowing it to sink inside the tank, but it can be able to stand upright when it reaches the bottom. So, what you need to do is to glance through the front of the aquarium in order to take the temperature reading of the thermometer. The problem with this type of thermometer is that it can be very hard to read especially when placed near the rear of the aquarium. But if you have a small aquarium, then you won’t get any problem reading from any point of the aquarium.  The other problem with this type of thermometer is that fish can easily hit it making it topple over forcing you to use your hands to make it stand upright again.


•    Inexpensive

•    Not impacted by ambient room temperature

•    Can be placed in multiple locations

•    Many have easily viewable “safe” zone


•    Scale may be small and difficult to read

•    Breakable

•    No alert feature

•    Less accurate than digital

iii. Suction cup submersible thermometer

Suction cup submersible thermometerThis is the best type of submersible thermometer. By attaching the cup of the thermometer to the glass of the aquarium, you can be sure that the thermometer will remain in the same position until the next time to check the reading of the thermometer. The good thing with this type of thermometer is that you can attach the cup anywhere in the aquarium. If you do not like the suction cup, then there are those that use the magnet to attach to the walls of the aquarium though they are less common.






•    It offers accurate readings.

•    It’s very affordable.

•    It doesn’t need batteries.


•    can be hard to read

•    Don’t use the suction cup on acrylic tanks, as it will leave ring stains that will prove very difficult to remove.

3. Thermometer sticker strips

This type of thermometers are often referred to as LCD thermometers. The liquid in the thermometer can be able to change the color when the temperature of water changes. You just peel a sticker and attach it to the front of the aquarium and it will be able to sense the temperature of water through the glass. Isn’t it nice? The only problem with this type of thermometer is that the sticker is attached outside the aquarium meaning that its temperature change can be influenced by the temperature of the room. So, who wants inaccurate reading?  Also, stickers have limited lifetime. Do you still want it?


•    Easy to apply

•    Inexpensive

•    Unbreakable

•    Can be placed in multiple locations


•    No alert feature

•    Can be difficult to read in low light

•    Less accurate than digital

Digital vs. analog thermometer

Which one is the best for your aquarium? The old fashioned thermometer which you need to match the temperature reading is the analog thermometer. Actually, matching the reading of the thermometer is not necessary. Why can’t you just get temperature reading of your thermometer by just a glance? Actually, digital thermometers are so precise and can even be read by the oldest eyes. Therefore, digital thermometers are the best. Do yourself a favor and get one.

Advantages of digital thermometer

•    Accurate

•    Easily available

•    Have alarm system

•    Easy to read


•    Expensive

•    Require batteries to operate

•    Not all are accurate

•    Some are hard to clean

Advantages of analog thermometer

•    Inexpensive

•    They do not require batteries to operate


•    Inaccurate

•    Hard to read

•    Does not have alarm system