Soft corals
Alcyonacea
The order of soft corals is a group very rich in color and form. There are among others finger-shaped, lobed, crusty, branched or tree-shaped mostly brownish, greenish and yellowish but also in red, orange or violet. About 800 different species are described.
Unlike stony corals, soft corals do not have a solid calcareous skeleton. However, many soft coral species have small calcareous needles in their bodies that give them some strength.
Many soft coral species live in symbiosis with algae. Photosynthesis feeds both species. However, some soft coral species filter their food from the water. This independence from sunlight allows these soft coral species to occur at greater ocean depths than, for example, stony corals.
| Related to | Cnidaria, Anthozoa, Soft corals |
| Habitat | Occur worldwide in all seas. Common in shallow-water inner reefs, tolerate temperature and salinity fluctuations. Also species in the deep sea and Antarctic Ocean. |
| Mode of life | In colonies of thousands of individual polyps |
| Structure | Branched, arboreal, crustose, finger-shaped, no skeleton, can contract |
| Diet | Mainly by photosynthesis of algae (symbiosis), but some also by water filtration |
| Size | Polyp a few millimeters in size |
| Reproduction | By releasing large amounts of eggs and sperm, but also by dividing the polyps, producing several new polyps |
| Commerce | In the aquarium trade (import only with permission CITES authorities!) |
| Aquarium keeping | Effortful |
| Population trend | Threatened by global warming and marine pollution. |
Distribution area: Worldwide in all seas.
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