The cauliflower coral (Pocillopora damicornis) is very common in the wild and in the aquarium trade. The cauliflower coral has been the subject of many scientific studies — in fact, more is known about this coral than any other. One reason that is it a common subject of research is because it is one of the easier small-polyped stony corals to keep in captivity. Aquacultured Pocillopora damicornis is especially durable and can survive under a variety of captive conditions.
Difficulty: While Pocillopora damicornis is a fairly durable for a small-polyped stony coral, a good light source is essential to keep the zooxanthellae (algae) that live in its tissue photosynthesizing — the byproduct of photosynthesis provides food for the coral host. Like other corals, the cauliflower coral also takes up both dissolved inorganic and organic nutrients, and the polyps also capture tiny planktors.
Physical description: Pocillopora damicornis forms compact clumps that can be up to 10 feet across. The branch structure differs depending on the habitat — in high wave energy environments, the branches are compact and sturdy, while in more protected areas, the branches are thin and less densely packed. The cauliflower coral color is usually light brown, green or pinkish.
Range: The cauliflower coral is one of the widest-ranging of the stony corals, having been recorded from the east coast of Africa and the Red Sea, east all the way to the Gulf of California and the coast of Panama. The cauliflower coral is found in a variety of different habitats, from mangrove swamps and turbid fringing reefs to outer reef faces. The cauliflower coral is most common at shallow to moderate depths (usually less than 80 feet).
Compatibility: The cauliflower coral is a fairly aggressive small-polyped stony coral that will extend 1-inch sweeper tentacles to sting nearby corals. The cauliflower coral is likely to get damaged by Rhodactis mushroom anemones and sea anemones. Fast-growing, plating scleractinians may overgrow and shade Pocillopora damicornis. The usual piscine suspects should be avoided in a small-polyped stony (SPS) coral aquarium, including butterflyfish, filefish, most triggerfish and pufferfish. Angelfish occasionally stray and nip at Pocillopora polyps, especially when they are not fed enough. This coral is an important home to a number of crab species (in one study, 25 species of crabs were taken from Pocillopora damicornis colonies). One of the most abundant are crabs in the genus Trapezius — these crustaceans may protect, provide nutrients for and occasionally feed on their coral colony home. The cauliflower coral is also often inhabited by groups of damselfish. These fish help keep fresh seawater irrigating the inner spaces in the colony and provide a source of nitrogen that enhances the corals' growth. In aquariums, the colonies often exhibit more boulderlike growth forms due to a lack of these associated animals that facilitate normal growth.
Aquarium conditions: Good lighting is essential to keep the cauliflower coral healthy. Lighting can consist of power compacts, T-5s and VHO fluorescents and/or metal halides. Moderate to strong water movement is appreciated by the cauliflower coral. Vigorous, oscillating water movement will help it shed fouling organisms and the slime it constantly produces. Keep water parameters for the cauliflower coral within this range: calcium 400 to 450 ppm, alkalinity 3.2 to 4.8 meq/L and magnesium 1200 to 1350 ppm. The water should contain no phosphates and the water temperature should be between 76 to 84 degrees Fahrenheit. However, studies have shown that the cauliflower coral shows optimal growth at two different temperatures: 81 and 87 degrees Fahrenheit. In the right conditions, the cauliflower coral grows very quickly.
Care considerations: The cauliflower coral is fairly disease-resistant. Filamentous algae is an enemy, as are red slime cyanobacteria — both of which can overgrow and “suffocate” this coral. Some have suggested that using carbon in your aquarium can cause the cauliflower coral to bleach.
Breeding: The cauliflower coral is a simultaneous hermaphrodite — that is, a colony can produce both male and female gametes at the same time. The cauliflower coral (and many other stony corals) have two different reproductive strategies. The first is brooding. This involves internal fertilization by sperm from nearby colonies with development of planula larvae which are brooded by the “mother” colony and then released. There is also external fertilization where the gametes are broadcast into the surrounding water column, were fertilization occurs, after which they develop into planktonic planulae. In some regions, Pocillopora damicornis releases planula larvae on a monthly cycle. Reproduction is synchronized with the full moon. Propagating this coral is very easy. Take a healthy cauliflower coral colony and simply snip off the end of a branch and attach it to a reef plug or piece of live rock with super glue gel or epoxy. When attaching the frag to the base, glue it on the side not on the end, and the cauliflower coral will grow more rapidly.