How to get Rid of Blue-Green Algae In Aquariums


How to Get Rid of Blue-Green Algae in Aquariums

Are you experiencing mysterious blue-green slime in your aquarium? Or is there a strange smell coming from your fish tank and you can’t find the source? You might be dealing with an outbreak of blue-green algae. In this article, we discuss the causes of blue-green algae and how to get rid of it once and for all.

What is Blue-Green Algae?

Blue-green alga (BGA) does not exist as an actual algae. It is actually a cyanobacteria, a group of bacteria that uses photosynthetics like plants. In freshwater aquariums, it’s known for its vivid blue-green color, but it can also appear in shades of brown, black, or even red. It may appear as a small spot of green algae, but it eventually becomes a thick slime that covers your gravel, decorations, plants, and other items. While cyanobacteria in aquariums does not usually harm fish, it can potentially kill your plants if their leaves are covered and can no longer photosynthesize light.

Another way to identify blue-green algae is by its distinct odor. People have described the smell as earthy, musty, swampy, and foul. Once you have learned to recognize the scent, it’s possible to detect cyanobacteria up to two weeks before it’s even visible in the fish tank.

Blue-green algae is actually a type of photosynthetic bacteria that comes in blue, green, brown, black, and red colors.

What causes Cyanobacteria in Aquariums

Many studies have been done to figure out what causes cyanobacteria blooms, since they can have a deadly impact on the environment. While there are no definitive answers yet, they commonly occur in warm, slow-moving, and nutrient-rich bodies of water. In the aquarium hobby, we have frequently seen blue-green algae pop up wherever organic waste has a chance to stagnate in certain areas of a fish tank. This could happen if:

– The current in the fish tank is too slow – Hardscape is blocking off a corner of the aquarium that also gets exposed to constant light – The substrate is collecting debris because the gravel hasn’t been vacuumed in a while and there are no animals to churn it

How can I naturally get rid of blue-green algae?

These possible causes are the basis for the first step: manually remove as much slime as you can using a siphon or toothbrush. Your clean-up crew will not be able to help you because animals don’t like blue-green algae. Remove any excess nutrients by doing water changes more frequently, cleaning the filter regularly, and reducing the amount of fish or food going into the aquarium (if overfeeding is a problem). Improve the water flow by using a stronger filter, adding a powerhead, or moving decorations and equipment around in the tank.

Because Cyanobacteria relies on photosynthesis to generate energy, many people recommend that the aquarium lighting be turned off for at least three to seven days in order to starve the colony. However, this method can end up harming your plants (which also use photosynthesis) or causing spats among the fish. The blue-green algae can also return within a few days.

Cyanobacteria can be treated with medicine

Many people have trouble dealing with this stubborn bacteria, but fortunately, it is very weak against a certain antibiotic called erythromycin. This medicine is safe for fish, plants, and invertebrates, and it will not harm the beneficial bacteria in your aquarium. Fritz Slime Out is our favorite, as it’s formulated to reduce cyanobacteria and not increase phosphate levels.

You can begin treatment by scraping off as much blue-green alga as possible. After vacuuming the substrate and refilling the tank, add one full dose of Slime Out (which is 1 packet per 25 gallons of water), and let the aquarium sit for 48 hours before doing a 25% water change. Add an air stone or other filtration that agitates the water surface to help ensure the fish have enough oxygen during the treatment. It is easier to eliminate an outbreak if you act quickly. If the blue-green algae is very thick and widespread, you may need to repeat the treatment several times to completely remove the colony.

If you address the underlying causes of cyanobacteria and treat it with Slime Out, you should have no problems getting rid of it in your fish tank. You can also find our complete guide to how to combat other types of algae in freshwater aquariums.