The Best UV Sterilizers For Aquariums

Aquarium UV Sterilizers help prevent the spread of bacteria and infections in a fish tank. Buying a UV sterilizer for your aquarium can help control free-floating algae and microorganisms. The UV light destroys these organisms, but it won’t get rid of organisms already attached to fish (ich) or rocks (algae).

UV sterilizers work alongside internal filters with mechanical filtration and active charcoal. Any free-floating microalgae or pathogens that the filter misses, the UV light will destroy.

So, if you want to control viruses, bacterial outbreaks that make your fish, algal blooms, green water and cloudy water, a UV sterilizer is the best investment you’ll make. You won’t need to change the water as often and it increases the longevity of your filter too (since it won’t have to work as hard).

Overview Of The Best UV Sterilizers For Aquarium

AA Green Killing Machine 9W Internal UV for Aquariums up to 50Ga

For aquariums up to 50 gallons. The Green Killing Machine allows water flow in direct contact with the UV lamp, making it extremely efficient. .

Sun JUP-01 U-V Filter for Aquarium Tank, Internal Green Water Killer

Can be used in ponds and aquariums. 4 function in 1 machine -water pump, air pump, filter, clean. A simple and effective ‘green water killer’.

Aqua UV 15 watt Advantage 2000+ Hang On UV Sterilizer.

The Advantage Series is ideal for small ponds, aquariums and water features; A UV Sterilizer is a proven method to eradicate bacteria, viruses and protozoa

Coralife Turbo-Twist UV Fish Tank Sterilizer 6X, Up to 250 Gallons

Removes free floating algae, parasites and harmful micro organisms from aquarium water; For fresh or saltwater applications

Best Aquarium UV Sterilizer Reviews

These are the best UV sterilizers for aquariums:

AA Aquarium Green Killing Machine Internal UV Sterilizer System

The AA Aquarium Green Killing Machine is easy to install and includes a powerhead. This UV sterilizer is fully submersible and does not need any plumbing to set up. There are suction cups to attach it inside the aquarium to allow water to flow through the UV light.

It features a sleeve that forces water through in a zigzag pattern to maximize ultraviolet exposure, thus improving its effectiveness. The AA Aquarium Green Killing Machine is the best all-round aquarium UV sterilizer.


  • Easy to install
  • Has powerhead
  • Mounting tools included (suction cups)
  • No extra setup equipment needed


  • May get loud over time

Sun UV Sterilizer For Fish Tank

The Sun UV Sterilizer is an excellent choice for both saltwater and freshwater aquariums. You’ll see a noticeable difference in water clarity within a day.

The built-in pump is convenient and effective at directing water over the UV light for cleansing. It works fine with tanks up to 75 gallons as well as outdoor ponds.


  • Water pump included
  • No extra setup equipment needed
  • Mounting tools included (suction cups)
  • Great for small – medium aquariums


  • No version for large aquariums
  • Motor problems after extended use

Aqua UV Hang-On UV Sterilizer

If you have a smaller aquarium, the Aqua UV Hang-On UV Sterilizer is perfect. It helps control algae and keeps the water clear without taking up much space in the aquarium.


  • Compact size
  • Excellent sterilization


  • Expensive
  • Not suitable for large aquariums

Coralife Turbo Twist UV Sterilizer

The Coralife Turbo Twist UV Sterilizer is the best choice for larger tanks because it can handle up to 250 gallons. It works with both freshwater and saltwater aquariums and features a powerful UV light.

It’s versatile enough to hang on to the back of the fish tank or you can in-line it along the rim. It has a bracket that clips onto the aquarium rim for added sturdiness when attaching it to the aquarium. But, you need to buy the pump and powerhead separately.


  • Best choice for large fish tanks
  • Powerful/long-lasting bulb
  • Can be used In-line or hang-on
  • Durable
  • Affordable


  • No water pump included
  • The bulb may become loose in the socket

Taam Rio Plus 1100 Aqua Pump and Powerhead – 382 GPH

Fully submersible; Energy efficient with high flow rates; For fresh or Saltwater aquariums

Marine color U- Tube with Directional Return 3/4 inch – 1 inch

U-Tube aquarium return with adjustable nozzle; Compatible with 3/4″ to 1″ tubing; For use with any aquarium water pump, wet/dry filter, canister filter, sump


Benefits Of Using A UV Sterilizer In Aquarium

A UV sterilizer is an excellent device used in aquariums to destroy bacteria, algae, and other problems like ich and other parasites. It one of the best ways to protect your fish tank. UV sterilizers are safe for use in both freshwater or marine fish tanks .

  • Kills harmful bacteria
  • Kills parasites
  • Gets rid of algae
  • Can reduce disease in fish
  • Makes your water crystal clear

A UV sterilizer is not a replacement for good in tank filtration. Both pieces of aquarium equipment work together to keep your tank safe and clean. If you keep algae eaters, you should supplement their diet with algae wafers since the ultraviolet light will destroy most of their food source.

How To Choose A UV Sterilizer?

As with aquarium heaters, choosing a UV sterilizer for your aquarium depends on the size of your aquarium. For example, larger aquariums need sterilizers with strong pumps to handle the water volume.

Luckily, the packaging or listing indicates the recommended fish tank size. For small tanks, try a hang-on back or inline filter to save space inside the tank.

Another vital thing to consider when buying an aquarium UV sterilizer is the power and wavelength of the bulb. The wavelength of the UV light tends to be around the same for most brands. But, some wavelengths are better at killing different types of pathogens/bacteria.

Also, check to verify that the fish tank UV sterilizer works with both saltwater and freshwater tanks. Some may only work on freshwater while others only work on saltwater. Be sure to read the information provided about the product to select one that fits your aquarium’s needs.


How To Install A UV Sterilizer?

Aquarium UV sterilizers come with instructions on how to set up and install the parts. Here’s a short video outlining the installation of a UV sterilizer:

How To Use A UV Sterilizer?

After installation, be sure to keep the pump of the UV sterilizer clean. There should be no blockages or buildup of debris. For sterilizers with crystal sleeves, you need to clean the sleeve as well. Ultraviolet light will lose its effectiveness if there is dirt or other debris buildups in the way.

Some parts will need changing after a while—for example, the bulb. There should be information on lifespan in the instruction manual. You will have to change some parts, such as the bulb, when they expire, and you need to to do water changes to remove the free-floating algae that the UV light killed.

Will A UV Sterilizer Kill Good Bacteria?

Yes. Aquarium UV sterilizers also kill the good bacteria, but only the bacteria that goes through the machine. Most of the good bacteria in your tank are on the filter media or in the substrate so they should be safe.

Will A UV Sterilizer Harm Fish or Plants?

No, UV Sterilizers do not harm your fish or plants, but it will make medicines ineffective so unplug it when treating your tank or fish with medication. If you’re just starting a planted aquarium (or any aquarium) wait until the nitrogen cycle is complete before running the UV sterilizer.

Is A UV Sterilizer Safe To Use In A Reef Tank?

Yes, UV sterilizers (and an excellent filtration system) are an excellent way to keep your reef tank clean. The main benefit of a UV sterilizer is that it helps to keep nuisances like algae, parasites and bacteria under control in your aquarium.

How Often Do I Need To Change UV Bulbs?

Recommendations vary from manufacturer to manufacturer, but you should change the UV bulb in your UV Sterilizer every 6-12 months. The more you use a UV light over time, the less effective it becomes, so it’s best to replace them every six months to ensure that you are getting the best sterilizing effects in your fish tank on a 24/7 schedule.

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