Why are you getting algae and where does it come from?

Types of Algae you might find in your aquarium

Today, we’ll be discussing the types of algae you might find in a Biota Aquarium or any saltwater aquarium. Many aquarists see algae as a nuisance and an evil, ugly pest in the aquarium hobby. The truth is: a healthy aquarium environment needs to have algae. Algae is one of the main components in the tank for fish grazing, nitrate and phosphate reduction, and stabilization. There are situations where things can get out of control and below I’ll explain how to identify and treat these issues.

Why are you getting algae/ where does it come from?

So, the main driving force of algal growth is available nutrients. Algae will only grow as long as there is an abundance of what they use to grow. Although there are many algae species and hundreds that appear in aquariums almost all of them thrive when there are excess phosphates and nitrates in the water. Just like adding fertilizer to your garden the fish in your aquarium constantly produce this nitrogen rich waste to help grow algae.

The second driving force of algae is light. Algae grows the most when they have an amazing light source like the one in the Biota Aquarium. If your light timer is on longer than normal you might see an algae outbreak and alternatively limited light could help slow or kill off some algae.

The general rule of thumb for limiting or removing algae is to limit and remove these driving forces. If you begin to see an outbreak you could try adding a few Chemi-Pure Blue packets to your aquarium to soak up some of the excess nitrates and phosphates before the algae can utilize it. Another method is a dark period of a few days. Shut off the lights and cover the tank with some light inhibiting materials (like a black trash bag) and starve out the algae. Be sure to check on the status of your fish and corals during a blackout like this because you’re also starving xoazanthellae in the corals with this method. Also if trying the blackout method be sure to have adequate water movement on the surface because when the lights are off algae respires taking oxygen out of the water column.

There are a few types of algae that seem to survive all of these methods and I’ll list them below with some other commonly found aquarium algae.

Types of Algae:

The first type of algae I want to discuss is the green film algae. This is found mostly on the glass of your aquarium and is easily cleaned off. You might get frustrated at the rate it is returning but this alga responds very quickly to lack of light. This is also one of the best algae to have in an aquarium because many fish graze on it off the glass and rockwork. This is also easily controlled by simply cleaning it off the glass and is likely to return in waves.

Green hair algae is the next algae I want to discuss.

This is a very thin filamentous alga that is most likely to be found on your rockwork or spreading to the sand bed. This alga can grow very quickly if there are excess nutrients in the system. In the wild Biota Aquarium’s court jester goby feeds almost exclusively on this algae so he or she will be your first line of defense. The second line of defense is both a phosphate limiting tool like Chemi-Pure Blue as well as Vibrant bacteria. Both of these slowly kill and limit this algae in the aquarium without harming your fish and corals. If needed a new pipe cleaner can be used to get these algae off of your rockwork in extreme cases. Since green hair algae is incredibly filamentous it gets caught very easily in the fine bristles of a pipe cleaner making it an excellent tool to clean the rockwork.

The next algae is coralline algae.

This is a pretty expansive term used to describe both the green hard calcified algae (spot algae) you might find on your glass and the nice purple and blue coralline you’d find on your rocks and along the back wall of your aquarium. If coralline is present in your aquarium that means it is fully cycled and is doing well. Although this is a good sign for the health of your aquarium it can be an eyesore especially on the glass. The key to controlling coralline on the glass is early detection. The longer you let the small specks sit the harder they are to get off. If there are new holdfasts on the glass they should be easily removed by your magnetic scraper tool. If they have been there for a few days or weeks you might need to employ a harder substance such as an old credit card. In extreme circumstances, a straight razor blade or steel straight edge may be used and a few aquarium companies sell this. Just be incredibly careful as to not scratch the glass of your aquarium or harm yourself while cleaning up this alga. I would only do this on the glass of your aquarium as calcified algae is a great growing substrate for various species of corals on your rock and back wall of your aquarium.

The next type of algae I’d like to touch on is bryopsis.

This is one of the toughest types of algae and has frustrated aquarists for decades. Bryopsis is a tough type of thick hair algae that has a very strong holdfast on your rock or sand. This alga is also able to survive in low nutrient or low light systems so my previous methods of control do not work here. Very recently aquarists have learned a fluconazole treatment will kill this alga as well as not harm any fish, corals, or invertebrates in your aquarium. For the Biota Aquarium, it is 300 mg dosage. To prepare for this treatment you must take out the carbon or Chemi-Pure filtration and try not to do any water changes for two weeks. You’ll notice the bryopsis thinning and possibly turning slightly lighter. If you are able to catch this alga early its possible to prevent outbreak with Vibrant on a regular dosage.

The next types of algae I’d like to cover are the rarer and not as often seen algae. This includes gracilaria, caulerpa, and hypnea. These are thick algae that don’t normally hitchhike on corals or as spores in water. If found in an aquarium it is best to just manually remove before they can put in a “root” system. Usually easy to eradicate through removal they can be almost impossible if unnoticed or untouched for weeks. Some aquarists use these algae and chaetomorpha as a nutrient removal system in a separate flow through tank called a refugium.

The final type of algae I’d like to touch on is not really an alga.

Commonly known as red slime algae this red-cyanobacterium quickly grows and covers your substrate. This bacterium thrives in new aquariums and tends to just coat the entirety of the rock and sand bed causing stress to the other types of bacteria in the aquarium. The key to eradicating this bacterium is to have good consistent water quality, high oxygen levels in the water, and time. Cyano-bacteria will eventually soak up too many nutrients that it will cause a massive die off. During this period, you can dose Vibrant to outcompete the cyano-bacteria as well as ensure it isn’t covering your corals.

To control algae in your aquarium the key is identifying it early and acting. Many of these will occur in the first few months during the aquarium’s maturation period and you’ll likely never see them again. To help prevent outbreaks and control algae in an aquarium the best methods are utilizing Chemi-Pure or Vibrant while the natural method of a clean-up crew is also advised. Snails, hermit crabs, and shrimp will graze all day cutting down on your need for cleaning.

As always, I hope this blog post was informative if you have any questions or have a topic for me to write on next please let me know.

2 thoughts on “Why are you getting algae and where does it come from?

  1. I may have written about this as an individual question before if so I never received an answer but now that you are presenting these posts it might be of interest to others. The Long poly coral did fine for a month or so and then shriveled up so small for almost two weeks that I thought that it was dead. Then, it came back in bloom and now about 6 months later is has almost overgrown the aquarium, covering the rock, beginning to drop onto the sand and spread and growing off of the coraline algae on the black, pump wall of the aquarium. It has virtually overgrown the green (is it zoanthid?) coral so that I can barely see any of it and don’t know how it is doing. Can this be controlled? Should I simply begin to pluck it out? At this rate it will completely cover rock, sand and end wall. It looks good but I can’t enjoy the other corals.

    • Are you referring to the Pom Pom Xenia? The long polyp leather will take years to overgrow the other corals. We recommend that you place both the Pom Pom Xenia and the Zoanthids in the sand so they cannot become a nuisance and take over your main live rock.

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