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How To Treat White Fungus On Live Rock!

The popularity of keeping live rock in aquariums is skyrocketing right now due to people realising just how beautiful properly cultivated live rock can actually be.

As with most things in aquarium keeping, there is a fine balance between having your live rock look exactly how you want it to look and having your live rock have problems.

We have seen a large number of people reaching out about the various problems that they have been having with their live rock over the last couple of months and already have an article going over dealing with white sponge on live rock.

Since publishing that article specific to white sponge growing on live rock, we have noticed more and more people reaching out with questions about dealing with general white fungus on their live rock.

Depending on your situation and what else you have living in your aquarium with your live rock, dealing with white fungus on your live rock can actually be more difficult than most people initially realize.

It really is not as easy as some other common issues with aquarium keeping where you are able to just apply a chemical treatment to fix the issue so we wanted to publish our own dedicated article going over what we would recommend that our readers do.

What Causes White Fungus On Live Rock?

White fungus is caused by a number of different types of fungal spores that are able to then grow into various types of white fungus in optimal conditions.

Due to most people who keep live rock trying to encourage coralline algae growth on their rock, this also presents the ideal conditions for various types of white fungus to grow too.

With most people wanting their coralline algae to be as bright as possible, they will also use a coralline algae growth accelerant that can help their coralline algae grow faster while also helping it keep its bright colors.

Unfortunately, these growth accelerators and nutrient products that are very popular with people keeping live rock are also nutrients for various types of fungus too.

This means if your tank does end up with some fungus spores getting into it, you can almost guarantee that you will have white fungus growing in your tank, often on your live rock.

All fish keepers have to deal with this risk though, especially those who use growth accelerants for their coralline algae but you are usually able to drastically reduce the chances of having issues with white fungus by quarantining any new additions to your tank before actually putting them in your main tank.

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How To Treat White Fungus On Live Rock!

The easiest way to treat white fungus on live rock is to use a chemical dip, usually with a low strength peroxide but this will usually cause problems with the other organisms on the live rock.

This is why most people tend to manually scrape the white fungus off their live rock even though it is time consuming and may require the rock to be scraped multiple times to remove all of the white fungus.

Depending on the stage of your live rock, it may be easier for you to dry your live rock and start from scratch then to try and clean a white fungus build up, especially if the white fungus has had a few weeks to set in.

If your coralline algae has grown in as well as various corals and other live plants then manually scraping the white fungus off the live rock is probably the best path to take.

Due to the texture and bumps on your live rock, the algae scrapers that many aquarium keepers use to get the algae and biofilm off their tank glass are essentially useless.

A single printed too or even a small knife is usually the best option to get a good scrape on the white fungus and remove it from your live rock.

Just remember that you should to try scrape your live rock out of the tank and out of water to prevent any fungus spores coming off into your tank during the scraping process.

How Can I Prevent White Fungus Growing On My Live Rock in The Future?

It is very difficult to prevent white fungus from growing on live rock as most live rock setups present optimal growth conditions for most types of fungus so a single spore can potentially result in large amounts of fungus growth.

The easiest method is to quarantine any potential new addition to your aquarium in a separate tank for a week or to and then add it to your main tank once you are happy it does not contain fungus.

If you are looking to add substrate, fake plants or decorations to your tanks the can be dipped in hydrogen peroxide or any other purging agent then you can often just treat them with chemicals to destroy any fungal spores.

After treating them with a chemical be sure to correctly clean them in fresh water baths to remove all traces of the chemicals before adding them to your tank as tanks with live rock in them tend to have sensitive plants and corals in them.

Other than that, just take all of the normal precautions that people take to prevent their tanks from having issues with fungus and the majority of people should be fine.

Just keep in mind that live fish can consume some types of fungus and pass it with the fungal spore still being able to germinate so you can also quarantine any new fish you are planning to add to your tank too.


That brings our article going over treating white fungus on live rock to an end. The majority of people should easily be able to scrape any white fungus off their live rock without having any serious issues. Just keep in mind that the longer you leave your white fungus the harder it tends to be to scrape off or remove from your live rock so we would recommend that you try to deal with it as soon as you notice it in your tank if possible.