Are Fans Bad for Fish? (13 Things You Need To Know)

Fish are popular pets worldwide. They are relatively easy to keep, are generally tranquil, are low maintenance, and can be very rewarding companions.

Are fans bad for fish?

Fans are not bad for fish. Aquarium fans help cool and ventilate fish tanks and aquariums. Desk, tower, or ceiling fans can blow over the surface of fish tanks to keep the water cooler, circulate oxygen, and discourage the growth of algae. Do not use strong or loud fans with fish.

In this article, I’ll answer the most common questions I get about fans and fish.

Are Fans Bad for Fish? (Answers for 8 Types of Fans)

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Glowing fish tank—Are Fans Bad for Fish?
Image by the author via Canva—Are Fans Bad for Fish?

When it comes to fish, there are many types of fans that you can use. However, most people ask me if eight specific fans are safe for their fish.

The eight types of fans include:

  1. Aquarium fans
  2. Desk fans
  3. Tower fans
  4. Ceiling fans
  5. Box fans
  6. Strong fans
  7. Loud fans
  8. Oxygen fans

Are Aquarium Fans Bad for Fish?

Aquarium fans are not bad for fish. Aquarium fans help make fish tanks and aquariums more livable.

You can get many different types of aquarium fans.

Popular types include:

  • Clip-on fans
  • Chiller fans
  • Co2 fans
  • Exhaust fans
  • Marine fans

Are Desk Fans Bad for Fish?

Desk fans are not bad for fish.

Fans can be used to lower the temperature in fish tanks, move oxygen through the tank, and hinder algae growth.

When using a desk fan, you probably want to use a low setting.

I also suggest that you direct the gentle airflow directly over (not into) the water.

Are Tower Fans Bad for Fish?

Tower fans are not bad for fish.

In much the same way that desk fans can help fish tanks, tower fans can also help circulate air and keep the water cooler.

One of the benefits of tower fans is that they are tall.

You may not even need to raise a tower fan or sit it atop anything else for the airflow to reach the surface of the water.

Are Ceiling Fans Bad for Fish?

Ceiling fans are not bad for fish.

In fact, using a ceiling fan is one of the best ways to cool your aquarium. A ceiling fan will cool the aquarium as the water naturally changes from a liquid to a vapor.

Heat energy is released when water evaporates from the surface. This can cool the water quickly and make it drop in temperature.

Keep in mind that many people cover their fish tanks with a lid to keep the fish from jumping out.

When you use a ceiling fan over a fish tank, you may want to lower the water level or use a mesh lid with holes.

Are Box Fans Bad for Fish?

Box fans blowing from across the room (8 or more feet away) will probably have a negligible effect on fish or fish tanks.

If positioned at a distance, a box fan can blow over the surface of the water as well as a desk or tower fan.

However, a box fan placed too close to an aquarium can propel too much air, move around too much oxygen, and possibly create lethal oxygen bubbles in the tank.

You are much better off using a smaller desk fan or tower fan on low settings.

Are Strong Fans Bad for Fish?

Strong fans can be bad for fish.

If you have a powerful fan blowing on your aquarium, it can create a wind chill that may make the water too cold or too oxygenated.

It is best not to use fans with strong gusts near an aquarium.

Are Loud Fans Bad for Fish?

Loud fans can be bad for fish.

Most residential fans do not produce enough sound to bother fish underwater. However, industrial fans or very powerful fans might create vibrations that startle fish.

Low-frequency sounds can also frighten fish.

If you think like fish, this makes sense. In nature, loud noises and strong vibrations usually mean danger.

One way you can tell if your fan (or other noise) is too loud for your fish is to watch their reaction. If your fish dart away from the sound, it’s likely too loud.

Are Oxygen Fans Bad for Fish Ponds?

Oxygen fans are not bad for fish ponds.

In fact, using a fan can help aerate the water and keep it well oxygenated.

If you have a large pond or a pond that has been stocked to its fullest capacity, you can leave your fan on throughout the day in the summertime to keep the water oxygenated.

Can You Leave a Fan on Fish All Night?

Yes, you can leave a gentle fan on a low-speed setting on fish all night.

You can also use a timer or temperature-controlled fans. Timer-controlled fans start and stop at designated times.

Temperature-controlled fans can help keep aquariums within a set temperature range. This is important for both salt and fresh water tanks.

If the water gets too cold or too hot, it can be deadly to your fish.

Can Fish Get Too Cold?

Fish can get too cold.

The comfortable and liveable temperature depends on the type of fish.

For example, cold-water fish prefer temperatures below 68 degrees Fahrenheit. Tropical fish, on the other hand, like warmer temperatures—between 75 and 80 degrees Fahrenheit.

If fish get too cold, they can become sick or die.

How Do I Know If My Fish Are Too Cold?

The most common way to tell if fish feel too cold is to watch their behavior.

When fish encounter very cold environments, their metabolism will slow down. They get lethargic and stop eating.

They may stop moving altogether.

How To Safely Use Fans To Cool Fish

You can use fans safely with fish by following the guidelines in this article.

Here are the best tips for using fans around your fish tank:

  • Position the fan at a safe distance from your fish tank
  • To prevent noise, choose a quiet floor or desk fan over a strong industrial fan
  • Use a timer or temperature-controlled fan
  • Don’t use extremely powerful fans that can drastically change the temperature of the water
  • Get an aquarium fan specifically designed for use in or around fish tanks

Watch this video about how to keep fish tanks cool in hotter months of the year:

YouTube video by Nano Tank Reefer—Are fans bad for fish?

3 Good Reasons Fans Actually Help Fish

There are three good reasons fans help fish live better and longer.

Here are those three reasons:

  • Fans improve air circulation
  • Fans cool the water
  • Fans move oxygen through the water

Fans improve air circulation, which helps to reduce the likelihood of diseases spreading in the tank.

Fans also help to evaporate water, which cools the water. This is especially important in densely populated tanks with little room for evaporation to occur naturally.

Lastly, fans move oxygen through the water, which fish need to breathe.

Final Thoughts: Are Fans Bad for Fish?

Try not to get too overwhelmed with keeping the exact perfect temperature for your fish.

Fish are surprisingly resilient creatures.

The majority of them can survive in a wide range of temperatures, salinity levels, and oxygen concentrations. That’s why they’re able to thrive in some of the world’s most diverse habitats.

Read more about fans and pets:

The Guardian

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