Is Coralline Algae Good or Bad

Is Growing Coralline Algae Good or Bad For Your Tank?

One of the questions we get frequently asked is “Is growing Coralline Algae good or bad for your tank?”. Encrusting Coralline Algae is the sign of a healthy tank and is what gives many saltwater aquariums their vibrant colors. A good covering is the goal of most marine aquarists. We would have to say that growing Coralline Algae is good for your tank!

Coralline Algae exists in a variety of different colors ranging from green, pink, and white to purple and red. For the record, algae are not simple plants. They are far more complicated than you may think. There are the green, macroalgae such as Halimeda and Halimenia, nitrate scavengers like Chaetomorpha. There are red algae in the family Rhodophyta; coralline algae belong to this family. There are many other algae as well.

How To Get Encrusting Coralline Algae To Grow?

First, understand that coralline algae is algae and hence a plant life form. Like other algae, coralline needs certain nutrients to grow and flourish; likewise, it will not grow well if certain other nutrients are present. Like other algae, coralline algae need increased levels of calcium to survive and thrive.

Unlike brown, green hair and red slime algae (cyanobacteria), which frequently grow in your tank whether you like it or not, Coralline Algae must be physically brought into your tank in order for it to reproduce and populate the various surfaces.

Coralline Algae can be introduced to your tank by adding:

The more types of Coralline (green, pink, white, purple, red) that you add to your tank, the more you will see growing on your live rock, substrate and aquarium walls. Once you have some Coralline Algae in your tank, how do you get it to reproduce and spread throughout your tank? One simple method is to turn off all tank filters and skimmers, leaving any powerheads running. With a single-edged razor blade, scrape the existing Coralline off the front and side tank walls. The water current generated by the powerhead will spread the Coralline scrapings throughout the tank where they will continue to grow. After an hour or so, turn the skimmers and filters back on.

Does Coralline Algae Need Light?

As with other forms of algae, encrusting coralline algae require light. Exactly how much or little light or what kind of light is required for optimum coralline growth is the subject of debates. Since there are more than 1600 types of coralline algae, it would stand to reason that no one light suits them all: some prefer higher lighting, while others prefer lower lighting. Many aquarists have found that, as their tank lights get older and the spectrum and intensity fades, some of their Coralline growths actually increase and grow higher in their tanks. They also found that these growths die off in the more well-lit areas and increase in the lower and/or more shaded areas of the tank when the lights were replaced, while other types increased under the more intense lighting.

While lighting is important, maintaining excellent water quality may actually be the biggest factor in growing a good crop of coralline. Like hard corals, coralline algae is calcareous by nature, requiring many of the same conditions that corals require:

SG apx 1.024
Calcium – 350 to 480 ppm
Carbonate alkalinity between 2.5 and 4.0 meq/L (7-12 dKH)
Low Phosphates (close to 0)
Low Nitrates (5 ppm or lower)

Many aquarists have found that performing regular water changes will keep the phosphate and nitrate in check.


So we will leave it up to you whether you think Coralline Algae is good or bad for your tank. We would have to say yes though. Based on the breathtaking color it adds and its ease of growth, Coralline Algae can be the one addition that sets your marine tank apart from all the others.

We will be happy to hear your thoughts

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