Cactus Caulerpa

 Quick Care Facts

• Care Level: Easy   • Lighting: Moderate to High   • Placement: Substrate
• Maximum Size: 12"   • Water Conditions: 72-81° F, dKH 8-12, pH 8.1-8.4, sg 1.023-1.025
• Propagation: Runners, Clippings   • Coloration: Green   • Supplements: Trace Elements, Iron
• Origin: Worldwide Tropics   • Family: Caulerpaceae   • Species: Caulerpa

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Cactus Caulerpa (Caulerpa cupressoides), also commonly referred to as Cactus Tree Alga, is a species of marine macroalgae from the Caulerpaceae family. It is found in different variants around much of the world from Florida to Brazil, along both coasts of Africa as far south as South Africa and in tropical areas of both the Indian and Pacific oceans. Depending on the locale Cactus Caulerpa will vary in both size and shape, ranging from tall and slender to shorter and more bushy. This green caulerpasoecies species is best known for its long stiff stalks with clusters of notched blades, which resemble a cactus and provide this species with its common name.

It prefers to grow in areas with shallow, sandy bottoms, that are protected from strong water currents. It is typically found growing in sea grass beds or shallow water habitats up to about 10 ft, where it is generally growing amongst the sandy substrate, but will attach to rocks and coral fragments.

Cactus Caulerpa is a great macroalgae to keep in a marine refugium, where it will consume nutrients as it grows, then when pruned and the clippings removed from the refugium, those nutrients will be exported from the system. Basically acting as a long-term nitrate absorber that never needs replacement media, simply trim larger plants and let them regrow. The slower growth rate of this species of Caulerpa, compared to most Caulerpa species, also makes it more suitable for the refugium as it is not as invasive as some other Caulerpa species. Most hobbyists prefer the slower growing vertical structures of the Cactus Caulerpa than the rapidly spreading grass like Caulerpa variants (Caulerpa taxifolia), when it comes time to pruning and propogating.

This macroalgae also provides excellent habitat for small crustaceans, amphipods and copepods to live amongst the root and vertical structures of the plant providing them habitat. In addition to providing habitat for refugium critters and absorbing nitrate from the water column, Cactus Caulerpa looks really good with its bright green cactus like vertical structures, which makes it somewhat of a show piece plant for a marine aquarium refugium.

The Cactus Caulerpa macroalgae grows from a runner, which is a common name for the root like systems that grows along the substrate. The plants grow up from the runner via vertical cacti like branching structures. It can be proporated by removing the runner intact from your tank, clipping it in an area that is between two plants and planting the new runner to liverock or a different substrate.

Cactus Caulerpa (Caulerpa cupressoides) grows best in refugiums with proper lighting, a sand substrate and plenty of gentle water flow comprised of water from the display aquarium moving through the chamber where the caulerpa is kept. This will allow the Cactus Caulerpa the opportunity to absorb nitrate from the water column as it grows its runners and stalks. LED lighting designed for marine algae or simple full spectrum LED lights will grow this species just fine.