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Coralline Algae – The Ultimate Guide

Coralline Algae – What is it?

Coralline Algae is a type of red Algae in the order Corallinales. It is a desirable algae to have in a saltwater aquarium and its growth is an indication of a properly matured marine fish tank. It is commonly introduced into an aquarium by placing live rock into the aquarium. Coralline Algae enters the system as one of the many beneficial “hitchhiker’s” on live rock as well as on the shells of snails. For a full list of aquarium hitchhikers see our article, Live Rock Hitchhikers.

Coralline Algae exists in 2 forms:

  • Geniculate or (articulated) corallines – These forms include branching, tree-like organisms which are flexible by having noncalcified sections.
  • Nongeniculate or (nonarticulated) corallines – Nongeniculate corallines are your typical encrusting and plating reef tank variety. They are often very slow growing and will grow on live rock, coral skeletons, shells, glass, plastics, and other algae. Matured coralline crusts may produce knobby protuberances which provide microhabitats for many invertebrates. Other non-articulated corallines produce chemicals which promote the settlement of the larvae of certain invertebrates. It is a little known fact that sea urchins, chitons, and limpets would not actually exist if it were not for the protection by coralline algae formations.

corraline algae on a live rock

The Role of Coralline Algae in your Aquarium and in Nature

Coralline Algae is a colorful component to any aquarium and adds to the overall aesthetics of your live rocks, it plays an important part of reef health in a closed system such as your fish tank as well as in the wild.

  1. Coralline Algae is a crustose type algae due to its hard calcareous deposits contained within its cell walls. It acts as the cement which binds the reef materials into a sturdy structure which will protect the reef and corals from breaking up or dislodging during intense wave action. Coralline algae has even been used in the past for bone graphs and dental implants due to its natural cementing and adhesion properties.
  2. It out-competes other rapid growth nuisance algae like hair algae, green algae, diatoms, and mat algae (in a normal reef environment with proper water chemistry).  Coralline algae takes up real estate on live rock that other nuisance algae might take up. Most coralline algae species are epiphytic and have chemical defenses to fight off other nuisance algae from growing on it.
  3. It looks attractive and gives coloring to your aquarium. Check out some great looking examples of the vibrant color combinations on ARC Reef Live Rock and even more so on our Premium Live Rock

Coralline Algae Live Rock Aquarium and Saltwater Fish Tanks

Coralline Algae Coloring – Not Just Purple

When you hear the term “Coralline Algae”, the first thing that pops into your head is an image of an aquarium covered in purple. But did you know that there are over 1600 known species to date? The colors of these species are most typically purple, violet, lavender, pink, and magenta, but there are hundreds of different color variations, including red, blue, white, yellow, and green.  Our team at ARC Reef has a stain of coralline that is bright orange in color and it phosphorescence under UV and actinic lighting.  We are actively trying to propagate this very rare strain of algae to all our live rock for sale.  It is a very slow growing stain though, but in a years time, we expect all our live rock for sale to come with a splash of this particular strain. We are extremely excited about the future possibilities that this stain will have on possibly everyone’s tanks in the not so distant future.Coralline Algae in a Bottle live spores purple up algae accelerator

ARC Reef’s “Purple Helix

ARC Reef (Atlantic Reef Conservation) is an aquaculture facility located in Miami, FL that produces sustainable Live Rock for Sale for aquarium owners. We are currently working on propagating our Live Rock with a highly epiphytic species of coralline algae dubbed “Purple Helix”.  It is a vibrant color combination of purple and pink.  Most Live Rock that you find in a fish tank will look pale or washed out over time.  Purple Helix is bright and strikingly vibrant.  ARC Reef isn’t making any claims just yet but we are working on methods to ensure that this select species of coralline algae will continue to out-compete other species on our Live Rock long after you’ve placed it in your aquarium. Currently, ARC Reef is the only distributor that offers such a vibrant strain and has now started offering this strain for purchase with their new product called, Coralline Algae in a Bottle, Purple Helix. purple corraline algae on a live rock

How to get more Coralline Algae in your Aquarium

Coralline Algae will not appear in a tank or closed system on its own like other nuisance algae.  It must be introduced into your aquarium, usually from Live Rock or by hitchhiking in on snails and hermit crabs that were collected in the wild.  High-quality Live Rock will have dozens of different species and