Best Aquarium Chillers

Fish are coldblooded animals. Unlike warm-blooded animals, fish along with other poikilotherms cannot keep the internal temperature of their bodies at a fixed point. Their body temperature fluctuates with the temperature of the surrounding and this is really dangerous. All of us in the hobby of fish keeping, all around the globe live in various climate regions and the temperatures vary with changing seasons. At the same time, there are many breeds and species of fish that require varying temperature ranges to live and grow. For the species that need water temperatures to be slightly higher than our ambient room temperatures, we have already detailed and reviewed the best aquarium heaters available in the market.

So now, if you live in regions that are warmer or regions where summers push temperatures beyond the comfort zone of the fish you have in your tank, we have aquarium chillers. In today’s article, we will go in detail about the working of aquarium chillers, why and when you may need them, the various products available in the market along with their features. So let’s dive in.

What are aquarium chillers actually?

Think of a chiller as the opposite of an aquarium heater. While an aquarium heater is a device that heats up the water to a certain temperature and keeps it there, an aquarium chiller is a device that cools down the temperature of the water in the tank to a certain temperature. When these are coupled with a thermostat, the chillers do not just chill down the temperature of the water but they also keep it from rising above a certain level. These are installed in line with the external filtration system to cool the water as it passes through the chiller’s system.

Why do i need an aquarium chiller?

Basically, the idea behind keeping an aquarium chiller is that you are in need to lower down the temperature of your water as compared to the ambient temperature of your room. Now, why exactly would I need to do that?

  • In case you have species of fish that have their natural habitat in cold water like trout or bass, it becomes a necessity to hold the temperature of the water below certain levels.
  • You live in areas where the temperature all year round is on a higher range.
  • Even if you don’t live in and around the equatorial parts of the world, the summer may come with heatwaves or loo which makes it essential to throw away the heat in the aquarium water for the survival of the fish.  
  • Equipment like LED lights, some filters also contribute to raising the temperature of the water above the normal level, in such cases chillers work to nullify the heat from such equipment.
  • Remember, it is not just the fish from the arctic circle or temperate regions that need cooler waters. Fish even from the subtropical places need temperatures to be between 18°C to 25°C. If you live in areas where summer pushes beyond 30°C, this may create trouble for your fish. Hence, the need for chillers.

Best Aquarium Chillers

Here are our top five picks for the best aquarium chillers that are easily available in the market along with their key features.

Aqua euro usa max aquarium chiller

Our first product is an old player in this game and a wildly popular one too. The AquaEuro USA Max Aquarium Chiller is manufactured by the US-based Hamilton Technology.

Now, the company offers lots of variants of different power sizes and chillers that work for tanks of different volumes. There is the lowest 1/13 HP version that works on tanks up to 50 gallons, 1/10 HP that works up to 80 gallons, the ¼ HP version that works up to 170 gallons and the one we are talking about here, the extremely powerful one, the ½ HP version that works to chill down tanks up to a whopping 320 gallons. But if your thirst for more cold water is not yet satisfied, the company also offers Max 1 HP version which works on tanks up to a volume of 700 gallons. They have got everyone covered, from small home tanks to huge exhibition tanks. Just remember that we are talking about the AquaEuro Max ½ HP version. The features are more or less similar to all other versions with just the dimensions and power is different.

This is a huge unit. It stands 17.3 inches tall from the ground. The inlet and outlet valves are placed on top of the chiller unit and both of them are individually around 4 to 5 inches tall. So, incase you want to fit your chiller in some box (you shouldn’t) you will have to find a box that is much taller than 23 inches. It is 19 inches front to back and 14.2 inches sideways thick. It is a chunky, big piece of equipment and you will be hard pressed to fit it inside your tank stand. So make sure you have enough space around the tank to keep this big boy.

There are two fittings on top of the unit, one for incoming water that is to be chilled and the other one for outgoing water that is chilled. Both of them are of the same height and size. Both of them fit pipes of ¾ inches in diameter. But for all its massive size and huge dimensions, the unit only weighs about 50 lbs. This is because the casing is made up of light materials and it doesn’t have many heavy components within it. The insides of this unit are quite spacious for aeration and that makes it bigger but light too.  Talking about aeration, there are two panels on the bottom of each side that come off. These panels have screen air filters on the inner side and stop dust and larger particles entering into the chiller. There is another similar larger air filter panel in the front. Overall, this is a very effective chiller and it can drop down the temperature as low as 39°F.

The flow rate of the Max ½ HP is 315 to 795 gallons per hour. You might say that this is a very large range for the rate of flow of water. Yes, it is as it is decided not by the chiller itself but according to the flow rate of the pump and other circulation units attached to it.

Apart from that, it’s working current is 4.4 Ampere and rated voltage is at 110 Volts, the rated frequency is also 60 Hz.

This chiller is a powerful system for both freshwaters as well as saltwater water tanks. It has a digital LED screen along with three buttons on its side: the “Up”, “Down” and “Set”. You press the “Set” button for 5 seconds, it beeps and then selects the temperature you want your tank water to drop down to. So, it is quite easy to use and calibrate. It quickly lowers and maintains the desired water temperature. It has a corrosion-resistant titanium heat exchanger that helps it pull down the temperature effectively. Also, this unit has an anti-freezing system that protects the heat exchanger itself from freezing while the process of cooling down the water is done. So it is a very well thought machine. However, it must be kept in mind that it should be watched over while it is plugged in and should not be left switched on for longer than 15 to 20 minutes.

The compressor uses Dupont R134a as coolant s it is ozone friendly and has no adverse environmental effects. In case of a power outage, it has an automatic power surge shut off control which incorporates the last set temperature recall system. This protects the chiller and returns all the settings to the last set temperature.

It has a high British thermal unit rating making it largely efficient in removing heat with little energy consumed. At the same time, it is quite easy to install and use and also maintain and clean.

Key Features:

  • It offers a wide range of powerful chillers that can work from small tanks to larger tanks.
  • The LED screen with three buttons system is quite easy to use and set up.
  • The heat exchanger is made up of corrosion-proof titanium.
  • The Dupont R134a which is used as the refrigerant is environmentally friendly.
  • In case of a power supply cut off, the chiller returns automatically to the last temperature settings.

Petzilla aquarium chillers

Our second product comes from Petzilla and these come in the form of chilling fans. This means, that instead of your typical chiller with a box that consists of a compressor, a heat exchanger, a fan, and a cooler, this contains only a fan. And it is the air from the fan that cools and pulls down the temperature of the aquarium water. You can have up to 4 fans in a single unit. But the one we are talking about here is the unit with a single fan.

The body of the unit can be divided into two parts, the rectangular fan portion, and the horizontal clipping portion. The total length of the chiller when placed horizontally along the aquarium is 4.3 inches. The clipper portion is 2.5 inches in height and the fan is 3.8 inches in height. I suggest you look at the pictures of the measurement provided on Amazon to have a clearer understanding of the dimensions. However, a single fan unit doesn’t take up much space in the tank.

Now, how this thing works is that the horizontal clipper attaches the fan to the wall of the aquarium. Here is the catch, the width or thickness of the lip of the aquarium wall around the top of the edge should be less than ½ inches. More than that and you will be hard-pressed to clip it onto the wall. After clipping, the fan stands parallel over the surface of the water and not inside the water. When switched on, it works as a general room desk fan and blows cold air into the water dropping down the temperature by 2°C to 4°C. You may ask, 2°C to 4°C? Isn’t that a bit lower compared to other chillers with compressors? Yes, it is. This is suitable for people who want to cool off the water in the tank down by a few degrees and not spend hundreds of dollars in the process. If you are someone who needs to have the temperature down by several degrees this isn’t for you. This is also particularly useful for cooling down the additional heat produced by LED lights and UV filters. You also have 90 degrees of turning angle or variable angle as it is called, to allow you to tilt the fans according to your liking.

It weighs only 11.2 ounces so it doesn’t create any problem on your aquarium wall. One single fan is powerful enough for a 10-gallon tank and no more. For greater tanks, you will need more fans. The fans also have two speed settings, one low and one high. When on high, the fans run quite fast and should be used carefully as they may disturb the water surface very much. A single fan runs on 12 Voltage and consumes just 1.9 Watts of power. It has a power cord that connects the fans to the power source. The cord however is a bit small.

The company provides with 1 year warranty too.

Key Features:

  • It is simple to install and simple to use.
  • It is light, portable, its position can be changed easily too.
  • If you want a device to negate the heating effects caused by the LED lights, filters and other equipment, and not drop the temperature of your tank by too much, this is the perfect equipment for you.
  • Let’s be honest, these fan units are way cheaper and consume less power than traditional chillers 

Jbj aquarium arctica titanium chillers

The third product on our list comes from South Korea. And I am no going to lie, but the Aquarium Arctica Titanium Chiller from JBJ looks like something straight out of the 80s or an early 90s CPU perhaps or something out of the Stranger Things. It may look dated but it does its job superbly well.

It comes in five different power options. The lowest being the JB1133 1/15 HP that works for tanks up to 40 gallons. Then we have the JB1111 that works up to a tank of 130 gallons and has 1/10 HP rated power. The JB1113 has 1/5 HP power and can be used for tanks up to 180 gallons.

We have the ¼ HP power rated JB1115 that works up to 260 gallons and the largest 1/3 HP rated JB1117 that works on tanks up to 340 gallons. As a reference, we will be using the JB1113 model that has a rated power of 1/5 HP.

This model is yet another bulky chiller, at least looks-wise. It rises almost 21 inches from the ground. It is almost 10 inches side to side thick and 16.5 inches front to back. It has two hose heads, one for an outlet and one for inlet hose on the top, like two new horns of a baby goat. This is 49 lbs making it slightly heavier but not too heavy. It draws in a current of 5 amperes and works on 115 Voltage. It has a high BTU rating at 2400 BTU per hour. The inlet and outlet hose head sizes are ½ inches, 5/8 inches, and ¾ inches. It is corrosion proof and uses the environment-friendly R-134a as a refrigerant.

It reduces the energy consumption costs through its custom-engineered JBJ titanium coil which maximizes the contact of water with the cooling coil for pulling down the temperature fast. The condenser is also corrosion resistant and is located on the front side of the unit. It has a built-in thermostat and digital controller that lets you set temperatures as close as 1°F with each other. Just like our first product on the list, the JBJ Titanium also prevents the freezing of the chiller itself by using an anti-freeze system. As with every chiller, this also needs a separate water pump to supply a certain water flow. The recommended water flow should be between 480 gallons per hour to 1320 gallons per hour.

Apart from all these features, it has a bright LED screen with simple two button set up system.

These JBJ chillers come with UL listings and a 2 year warranty further enforcing their reliability.

Key features:

  • The custom JBJ Titanium coil is so made that it maximizes the contact of the water with the titanium strips containing the refrigerant. This cuts down power consumption and makes it more efficient.
  • You can lower down the temperature as close as 1°F apart from each other. Meaning that you can go from 72°F to just 71°F if you wanted to.
  • It also uses environmentally friendly R134a as a refrigerant.

Londafish aquarium chillers

LONDAFISH bring to us the second fan based cooler on our list and these too are simple and do their job without much fuss.

These come in two fans unit. And just like the last fan chiller, these two can be divided into two parts. The square fan body and the horizontal clipper that holds the chiller to the aquarium. The clipper elongates 20.3 cm horizontally while the total unit is 16 cm in height.  These adjustable jaws clamp on the aquarium wall but their thickness should be no greater than 1.2 cm.

These run on a 100 to 240 Voltage and have a power cord that is 47.2 inches long. These come with a DC 12V power adapter.

The width of the fans is adjustable as well as there is an adjustable angle up to 100°. This allows you to direct the blow of the air at any place in the tank. A unit of two fans can cool down the temperature of the water to 2°C to 3°C.

Apart from all these, this chiller comes in easy to install and use packaging. It requires absolutely no assembly and you can just hook it up on the aquarium wall and start using it. However, the fan is not as quiet as they are claimed to be.

Key Features:

  • Assembly and usage is incredibly easy.
  • This unit costs way cheaper and consumes way less power than traditional chillers do.
  • The variable angle is as large as 100° so that you can focus the airflow from the fans to any specific part in the tank.
  • The maintenance and cleaning are quite easy too.

Iceprobe thermoelectric aquarium chiller

As the name suggests, this is a “probing” chiller. We have covered huge bulky box-like chillers, fan units, so we think it is only natural to add more diversity on our list by adding the classic Iceprobe chiller.

Before moving into what it actually is and the features, let’s just quickly get the size of this thing out of line. It is quite a compact unit with 4 inches × 4 ¾ inches × 7 ½ inches of dimensions, these sizes include the probe itself too.

This is the perfect cooling solution for small-sized aquariums, up to 10 gallons. It contains a probe that penetrates into the tank. For that, you need to drill in a 1.25 inches hole into siphon overflows, pre-filters, sumps, or for acrylic aquariums even directly on the wall. It comes with a nylon nut and silicon washer that hold the entire unit in its a place on the tank. The probe requires three 1/8 inches of clearance inside the tank.

It is very efficient as it directly uses the electric power from the source to chill down the water. It can cool 10 gallons of water from 6°F to 8°F below the ambient air temperature. A single probe doesn’t, however, work as effectively on tanks above 10 gallons. Due to its efficiency, it draws in less than 50 Watts of power. It also weighs just at 2 pounds and is powered by a 12V DC power supply. It has a heat sink and a fan above the heat sink that dissipates the heat to the outside. The fan is also relatively quiet.

It is easy to install and operate. It doesn’t have an on/off switch. To switch it off you will have to switch off the switch from the main socket. This means that you will need a separate power socket dedicated to this chiller or you will have to use a separate temperature controller to turn the device on or off at pre-determined temperatures. The cord is 5ft 9 inches while the probe cord is 6ft.

It uses no harmful chemicals or gases and is environmentally friendly. And the manufacturer also adds a 1 year warranty.

Key Features:

  • As compared to traditional big bulky chillers, this is a very compact and small unit that doesn’t take much space around the tank.
  • Also compared to traditional chillers, this goes on about its job quietly and makes little noise.
  • The electric energy is directly used in cooling the water without any intermediate processes as seen in other chillers. This makes it more energy-efficient and cuts down on electricity bills.

Our top pick

Now choosing the best aquarium chiller for your tank depends, totally, on you and your needs. But according to the panel of experienced tank keepers here, we say that Aqua Euro Aquarium Chiller is the best in its class. It comes in all power ranges, for bigger as well as smaller tanks, it pulls down the temperature of your water quite well and without fuss. In case of a power outage, the chiller automatically returns to the latest set temperatures. It has no complicated assembly or setup, just plug it in and it is ready to go. It doesn’t promise you anything posh, it is just a true blue-collared head down worker kind of chiller in the sense that it does what it says. The easy of use, maintenance, and durability is quite easy. Therefore, it is our top pick from the list.

How does an aquarium chiller work

OK. This is a bit complicated question but let me try making it as simple as possible.

Most chillers that we have featured in our list have outer boxing that essentially contains 4 major compartments that act in tandem to take in relatively hotter water from the tank and flush cooler water back into the tank.

The first compartment is where the exchange of heated water from the tank enters and finally after cooling down also re-enters the tank. It has a series of metal coils that are filled with refrigerants. R134a is a popular refrigerating agent used in modern-day chillers. These are environment friendly and do not cause any harm to the ozone layer. This chamber is where the heat from the water is given off to the refrigerant and the water which is now colder than when it entered returns back to the tank. So, our water is cooled in just the first chamber. But the refrigerant which is now hot as it has taken the heat from the water and it needs to be cooled down.

From the heat exchanging compartment, the refrigerant that is now carrying the heat enters the compressor where under pressure it is changed from liquid into gas. The difference in air pressure in the compressor drives the now vapor form refrigerant out of the compressor box.

The gaseous refrigerant then passes through a box that has a fan blowing over it. This cools it down and expels the heat to the surrounding.

Next, the gaseous refrigerant that is now cooled down passes into the last chamber which is the condenser. Here, it condenses back into liquid form. But the liquid refrigerant from the condenser before being sent back to the first chamber passes through an expansion valve. This expansion valve helps control the rate at which the aquarium water is cooled inside the first chamber.

What are the things I must consider if I get an aquarium chiller?

  • The flowrate of the chiller is not decided by the chiller itself, but by the pump that accompanies the chiller. Hence, you will need to see what are the asking flowrate of the chiller is and choose a pump likewise.
  • There is always a fan in your chiller. The fan serves to take the heat from the water and expel it to the environment. Thus, you need to make sure that the chiller is placed in such an area that is well ventilated.
  • The fan should be regularly inspected and cleaned to remove unwanted dust and particles caught in it.
  • Make sure you don’t use your chiller without water flowing through it. Dry running it can damage the internal motors.
  • Do not leave your chiller without proper monitoring. A chiller should not be left working on for more than 15 to 20 minutes.
  • Most chillers are a high power-consuming device. Be sure to check the power consumption before you buy the unit.
  • Check the internal components for calcium deposition which can decrease the efficiency of the unit.


So, there you have it folks. Our comprehensive, detailed study on aquarium chillers. There are loads of options in the market and you can even build DIY chillers at home. Chillers often are expensive and consume loads of power so you must be careful in choosing one. These devices are especially necessary if you have larger fish and live in areas where throughout the year or at least few months in a year, the weather pushes towards extreme heat. We have picked the best chillers in the market for you and have detailed the features, power consumed, space occupied and everything you need to know before buying one. Hope by now you have a better and clearer idea about which one to choose.

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