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Is A Black Light Safe For Aquariums?

Photographs and video of UV or black light aquarium setups often go viral on social media and each month, we see more and more people reaching out with various questions about using a black light for their aquarium to try and get these beautiful looking UV aquascapes that you see going viral.

The majority of people seem to think that any old black light will work for their UV tank setup but this is not the case and a number of UV light products on the market can actually cause major problems in an aquarium with some harming fish.

Thankfully though, there are a wide range of aquarium safe UV lights on the market that you are able to use in your blacklight aquarium that are safe for use with your fish and corals.

This can allow you to quickly, easily, and cheaply get that unique UV look to your tank without putting your fish or corals at risk.

We will offer a breakdown of a few different blacklights that you are able to use in your aquarium to get slightly different effects too as different products are optimised for different use cases.

We will also be going over the four most common questions that we have noticed people from the community asking time and time again.

The table of contents below will help you skip to the specific black light question that you have for a UV aquarium setup to help you save time too but as we said above, you can’t just use any old UV light in a black light aquarium so we would recommend that you read the full article if possible.

Are Black Lights Safe For Fish Tanks

Many of the long wavelength UV lights can be used in aquariums and will not cause any issues with your fish or corals but short wavelength UV lights should be avoided at all costs.

A short wavelength UV light can cause a wide range of potential problems in your fish tank and they have very specific use cases that are not based around fish keeping so always stick to a long wavelength UV light that has ideally been specifically designed for use in an aquarium.

The majority of people who want a black light setup for their tank want it for one of two reasons, either to display their fish with Glofish being one of the most common additions to a black light aquarium or they want the UV light to display their corals.

We would always recommend the Glofish UV fish display light for display fish and although it can work well for displaying corals too, its output can be a little low so an actual coral UV light should be looked into if showing off your corals under a black light is your main goal.

There are also a number of specialist products on the market such as various UV algae bloom lamps that have their own specialist use cases.

Some of these can be used in a tank with your fish still in it but others will require you to remove your fish and other living creatures from the tank before use if they are being used to deal with an algae bloom.

Is A Black Light Good for Fish Tank?

A black light is a purely aesthetic feature for the vast majority of people and there is usually no functional requirement for it.

You are able to get some unique looks to UV aquariums by using a black light to illuminate it though with many people enjoying the unique look that it provides the tank as it really can make a display tank stand out and catch the eye.

As we mentioned above, you can get a cheap UV fish display light to show off any fish you have that will react to being under a black light but at the time of writing, the vast majority of these fish are from the Glofish brand.

Due to local laws, these fish are banned in many areas due to being classed as a genetically modified animal so our readers in Europe will often struggle to find the fish for their tanks.

The popularity of keeping reef tanks with various types of coral such as zoanthids that will react under a black light is increasing at a rapid pace now so a coral UV light can really make these aquarium designs pop and stick out.

The UV black light products that have been designed for use with corals do tend to have a higher output too making Glofish or jellyfish that react to look even brighter.

How Do You Make A Black Light Fish Tank?

There are a wide range of different black light aquarium setups that you are able to use depending on your goals and the type of aquarium you keep.

Many people who have suitable fish that will react to a black light can easily setup a UV fish display light to have their fish stand out but setting up a UV reef tank to have corals and anemones that react to UV light stick out does take more experience and beginners should probably build up some experience before trying it.

As we touched on earlier in the article, we would highly recommend the Glofish UV fish display light if you are just wanting to display fish that react to UV light as it is cheap, easy to setup, easy to use, and works very well.

There are a number of other UV fish display lights on the market that can work but they just don’t have enough going for them to even come close to challenging the dominance of the GloFish light.

When it comes to setting up a black light reef tank, you really do have countless options depending on exactly what you want, the size of your tank, and the corals that you keep.

A decent coral UV light will be able to help the majority of our readers get started with the project but larger tanks really do open up a large number of possibilities with multiple light rigs to get unique looks from your corals but this does push up the price tag required for the tank.

Does A Black Light In A Fish Tank Cause Algae?

Although some people think that a black light in an aquarium will cause algae, the opposite is actually true with a black light often being able to sterilize many types of algae commonly found in tanks.

There are a number of special products on the market that have been designed for this purpose and many fish keepers use them to deal with various types of algae blooms in their tanks.

Just keep in mind that a decent UV algae bloom lamp is able to treat some types of algae but not all of them.

The majority of these lamps will deal with single celled algae and the higher price point lamps can sometimes deal with other types of algae too but there are a number of algae types that are not affected by a UV algae lamp.

We often see people complaining on social media that their UV algae lamp did nothing for their tank but when you look at the type of algae that they were trying to treat, the product clearly says it is only for single-celled algae.

This is why we don’t usually recommend these UV algae lamps to people new to keeping fish as they are not as easy to use as many people think and some people accidentally leave their fish in the tank during treatment where as some lamps clearly recommend that you remove your fish to prevent any potential harm to them.


That brings our article going over using a black light for an aquarium to an end. We hope that we have been able to help our readers better understand the different types of aquarium safe black light on the market right now as well as how they are able to be integrated into a number of different UV light aquarium setups. Although these tanks do catch the eye, many of the people reaching out about them only do so due to seeing the vital photographs on social media of the tanks and many of the people fail to realise how much care and money a correctly built reef tank requires making it harder than most people initially think.