Getting Rid of Bryopsis and Other Types of Hair Algae in Your Aquarium

Sooner or later, most saltwater hobbyists, especially coralheads, experience the disgust, heartbreak, alarm, lower back pain, and horror of Bryopsis or another species of hair algae growing out of control in one or more areas of their tank. If they’ve never had to deal with it before, a hobbyist might actually like watching how it flows with the current in their tank in the beginning, adding an element of green, blue-green, or brown motion. However, the novelty quickly turns to shock as the algae rapidly explodes into a thick and ever-lengthening mat of yuck that begins colonizing other areas of the tank, smothering prized corals and turning the whole display into an unsightly mess. Whichever one or more species of hair algae are getting established and ruining the look in your tank, the steps you take early on can make the difference between restoring your display to looking great with a little time and effort or wanting to drop a grenade in it and start over.

Here are some options for hair algae removal in your reef tank:

• Best defense is a good, motivated offense – Recognizing a hair algae outbreak when it is quite small simplifies everything. When you see the first tufts of any kind of hair algae growing on live rock, try to find out what it is and go right after it. This is a problem that simply will not go away by itself. It will quickly become exponentially worse and a multifaceted approach to removal and treatment will likely provide the best results.
• Reduce nutrients in your system – Run a battery of water quality tests and pay special attention to nitrate (NO3) and phosphate (PO4.) These nutrients are like rocket fuel for hair algae and unless you get those values down, you’ll never be able to turn the corner on this scourge. Perform aggressive water changes and consider adding some kind of chemical filtration to your system with media that absorbs these nutrients.
• Reduce lighting intensity and photoperiod – For coralheads, this will be especially difficult but it must be done, as the same wavelengths of light that feed your photosynthetic zooxanthellae also trigger other undesirable types of algal growth. Stop feeding the beast and it’ll be easier to starve, stop the spread and remove it. You might even turn the lights all the way off for a time. For reef tanks, this is a good short-term solution but don’t starve your corals for more than a few days at the longest.
• Physical removal – This can be tedious, depending on how bad the outbreak is but also very effective when used in combination with other methods of hair algae control. Set aside two buckets and get to work. Reach in and grab clumps with your fingers and rinse your hand in the first bucket, then rinse it again in another bucket to help ensure that you’re not reintroducing it back into the display. You may also want to turn off powerheads and the main system pump to prevent small pieces from getting carried away in the current and starting new growth in other areas. This will likely need to be done several times as the remaining portions continue to grow but if you stay with it, it’ll work eventually.
• Janitorial livestock – There are fish and invertebrates that actually like to eat hair algae but it’s a bit of a crapshoot, as not all species taste the same or are favored by emerald crabs, tangs, snails, nudibranchs, and other clean-up crew critters. Sometimes, it can vary by individuals, as some yellow tangs will go right after the stuff while others ignore it completely. Your mileage may vary on this but if you choose the livestock approach, make sure the janitors you choose will get along with or are safe from the other inhabitants in your tank. Some of these critters might prefer the taste of coral polyps to hair algae. This approach is definitely not foolproof or without peril.
• Strong, direct flow – Your mileage may vary on this one, too, but generally speaking, hair algae does not tolerate strong, direct flows for long. The strands get torn apart by the current, except for the stuff encrusted on your live rock, of course. This can work if you’re willing to surgically spot-siphon the rock and other aquascaping in your tank to prevent these wayward strands from landing and starting up in new areas.
• Fluconazole – This medication is favored by some while others have reported mixed results. Again, your mileage may vary but overall, this drug can be safe for reef aquaria, provided you follow the dosage recommendations. You’ll also want to take your skimmer and UV sterilizer offline during the treatment and follow up with aggressive water changes after the prescribed period of time. The skimmer will take the medicine right out of the solution and the radiation from your sterilizer can affect the efficacy. If your system has a refugium with some type of algae for nutrient control, you’ll want to find a safe place in another system or this drug will nuke that, as well.
• Other types of chemical warfare – There are over-the-counter products often found in fish and coral stores, some of which are pretty effective and others which are snake oil. It’s best to do your research on each before buying. Some reefers say that direct application of hydrogen peroxide to the problem areas is effective but it’s not without peril, as H2O2 is also toxic to fish and invertebrates. If you go this route, use a syringe and be very, very careful. Other coral heads have found success using targeted applications of Aiptasia control products containing calcium hydroxide. Again, you’ll want to be very surgical with the application or you can nuke prized corals and other desirable inverts and perhaps even some fish. You may be tempted to use one of these shortcuts to save time and reduce the hassle of hair algae removal in your aquarium but they are not without the potential for unwanted collateral damage.

Our Pledge to Our Customers

Believe us when we say that we despise hair algae even more than you do and on the rare occasions that some are noted in one of our systems, we prosecute that stuff with extreme prejudice and malice aforethought. We use strict quarantine protocols to keep it out of our systems and more importantly, to keep it out of our customers’ systems. This is why each online coral frag we sell is carefully examined before shipping to help ensure that our customers only receive the healthy, vibrant coral frags we’re known for and none of the hitchhikers that we all loathe. Here’s hoping you never have to deal with Bryopsis or any other kind of nuisance algae in your reef tank! If you do, above is a list of measures you can take to minimize the damage, time spent, and frustration of dealing with the stuff. Thanks for reading and good luck!