What Is an Aquarium Fan? (Explained for Beginners)

If you are a fish keeper, it is important to monitor the temperature of your tank. One of the best ways is to use an aquarium fan.

What is an aquarium fan?

An aquarium fan is an electronic device designed to move air through or around an aquarium. Aquarium fans prevent stagnation, which can be deadly to both fish and plants. They also help to maintain the temperature of the tank by mixing warmer waters with cooler waters.

In this article, I’ll answer the most common questions people ask me about aquarium fans.

Types of Aquarium Fans

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Aquarium Fan with fish—What Is an Aquarium Fan
Image by author via Canva—What Is an Aquarium Fan?

There are a few different types of aquarium fans, but all have essentially the same function: to circulate air in the tank.

Common types of aquarium fans:

  • Saltwater aquarium fan
  • Marine fan
  • Clip-on aquarium fan
  • Exhaust fan
  • CO2 fan
  • Dwarf fan
  • DIY aquarium fan
  • Aquarium fan with thermostat
  • Aquarium chillers

What Is a Saltwater Aquarium Fan?

A saltwater aquarium fan is a cooling device with a propeller attached to a motor.

The propeller is usually fitted with a grille that prevents fish from getting stuck in it, and the motor is connected by an electric cable to either a battery or power supply.

You use a saltwater aquarium fan for cooling or circulating air through your marine aquarium.

What Is a Marine Fan?

A marine fan is used for cooling down saltwater fish tanks.

Therefore, a marine aquarium fan is just another name for a saltwater fan.

There are different types of marine fans, including small clip-on fans that are designed specifically for smaller tanks to larger fans attached to larger aquariums.

Another type of marine fan is used in boats.

What Is a Clip-On Aquarium Fan?

A clip-on aquarium fan is a small electrically powered aquarium cooling system with a frame, motor, and propeller blades.

You use it much like you would any other type of aquarium fan.

The big difference with this fan is how you attach it to the tank. With a clip-on fan, you attach it to an outside edge of the tank with a clamp.

What Is an Exhaust Aquarium Fan?

An exhaust fan is designed to move air through or around your aquarium while venting moist air and odors out of the room.

There are two different types: stand-alone and inline models.

Stand-alone fans attach directly to your aquarium or to a built-in canister filter. Inline fans fit between the water pump and a series of canisters.

You can also use an exhaust fan in a canopy above your aquarium.

What Is a CO2 Aquarium Fan?

A CO2 fan speeds up plant growth by increasing carbon dioxide levels in your substrate. You use it as part of a CO2 system to grow healthy plants.

The fan helps to create the optimal conditions for efficient photosynthesis.

What Is a Dwarf Aquarium Fan?

A dwarf aquarium fan is an air pump that has four or more outlets. They are designed for small tanks, but they can also be used in large tanks.

You use it by taking the air line coming out of your return pump and attaching it to one of the outlets on the air pump.

Some people also use the term “dwarf fan” to mean a small fan for a small fish tank.

What Is an Aquarium Fan with Thermostat?

An aquarium fan with a thermostat is designed to control the temperature in your tank.

The device has an internal thermostat that monitors the temperature of your aquarium.

If it rises above a certain level, the fan kicks on and moves air over or around the tank. If it drops too low, then the fan stops moving air until the temperature stabilizes again at a safe level.

What Is a DIY Aquarium Fan? (With Video Instructions)

A DIY aquarium fan is an inexpensive way to provide fresh air for your tank that doesn’t come in a store-bought package.

All you need is a computer fan, an electrical cord, and a way to mount the fan.

Here is a good video that shows you how to put one together from start to finish:

YouTube video by Crazy F India—What Is an Aquarium Fan?

What Is an Aquarium Chiller?

An aquarium chiller is not technically a fan but is related.

A chiller cools down your aquarium water. It does this by drawing heat from the water and dissipating it into the surrounding environment.

A chiller stores cold water and/or lowers the temperature of the water that passes through it.

You can think of it as a type of refrigeration system.

You use an aquarium chiller because hot temperatures in your tank can adversely affect fish and plants.

What Does an Aquarium Fan Do?

An aquarium fan serves several important purposes.

First, it allows you to cool down your marine tank and make it a safe environment for your fish.

Second, it increases the oxygen content in the water and helps prevent CO2 levels from getting too high.

Third, an aquarium fan mixes up the air in the tank and helps keep bad bacteria from forming on the water’s surface.

What Does an Aquarium Fan Not Do?

It’s just as important to know what an aquarium fan doesn’t do.

First, an aquarium fan does not always turn on or off automatically. Some models do, some don’t.

I suggest that you purchase a fan with a timer or temperature gauge.

Second, an aquarium fan doesn’t necessarily make your fish more active. It can help with motivating more activity, but it is not a cure-all for lethargic fish.

Third, it doesn’t always circulate salt through the water to remove unwanted impurities.

As a general rule, freshwater tanks do not use salt.

An aquarium fan is simply a cooling device that increases oxygen content in the water and helps keep bacteria levels low.

How Does an Aquarium Fan Work?

Here is how an aquarium fan functions: You set up an aquarium fan on your tank, plug it into a power source, and turn it on.

The propeller blades spin methodically, creating circular currents that move water throughout your aquarium.

A few models also include a built-in temperature monitor that alerts you if the temperature gets too high or low for your fish.

Where Do You Put an Aquarium Fan?

Aquarium fans are typically mounted on the side or back of an open-top fish tank.

Place the fan so that air circulation is directed over the surface of the water. This will result in a slow flow of air across the largest surface area possible.

Do not aim the fan directly into the water.

How Many Circulation Fans Do You Need?

The number of aquarium fans you need is determined by the size of your fish tank.

Typically 1-2 fans are sufficient for a 10-gallon tank.

On the other hand, 3 or more fans might be needed to circulate water through larger aquariums.

How To Use an Aquarium Fan (6 Good Tips)

Aquarium fans are simple to use, provided you follow a few guidelines:

  1. Clean the grille on a saltwater aquarium fan with a toothbrush or soft-bristled paintbrush before first plugging it in for the first time.
  2. Plug your fan into a power strip or surge protector.
  3. Set up an aquarium timer that turns your fans on and off every few hours (or within a certain temperature range).
  4. Attach the fan onto the side of your fish tank with a clip or a suction cup.
  5. Use a mesh lid with holes or lower the water level when using a fan (fish might accidently jump into the fan).
  6. You should also make sure your fans are clean and dust-free before every use to keep them running smoothly. You can use a can of compressed air.

Should I Get an Aquarium Fan?

If you have a saltwater tank, it is a good idea to buy an aquarium fan.

They not only create currents that bring extra oxygen into the water but also help keep the tank at a safe temperature.

You can get a model that fits the size and shape of your fish tank.

Do Aquarium Fans Really Work?

Yes, aquarium fans really work.

They are essential elements in a livable ecosystem for your fish. My clients, friends, and family who own fish tanks all have fans.

According to them, the fans are necessary for the health of their fish.  

They say that their fish seem happier and healthier when they get a regular dose of circulating currents.

I think that aquarium fans are a good idea for all fish tanks because I’ve never known anyone who has regretted getting one.

How Much Does an Aquarium Fan Cost?

Aquarium fans range in price from $20 all the way up to $600.

The most expensive ones are high-quality models that include extra features like programmable timers, built-in temperature gauges, and automatic shutoffs.

You can find a good aquarium fan in the $20-$50 range. You can find a good chiller in the $200-$400 range.

Where Can You Find an Aquarium Fan?

You can buy a small aquarium fan at any pet store, but you will probably find a better selection online.

Here are a few places where you can buy aquarium fans:

  • Amazon
  • Bulkreefsupply.com
  • Petco

Which Aquarium Fans Are Best?

Aquarium fans come in all different types and sizes—each one is designed for a specific purpose.

Here are some of the best fans/chillers on the market:

CategoryBest Aquarium Fan
Budget-friendlyLONDAFISH Fan
Aquarium fan for AxolotlBAOSHISHAN
What Is an Aquarium Fan? (Best Aquarium Fans)

Final Thoughts: What Is an Aquarium Fan?

The cooling and ventilation system your build for your fish is crucial to their health and longevity.

Now that you know about aquarium fans, you might be interested in reading the following posts:


The National Fish and Wildlife Foundation (NFWF)

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