Like a carpet of tiny flowers, these animals are often seen in the wild on shores, growing on stones and coral rubble, as well as in turbid, high-nitrate areas in canals, harbors, intertidal areas and reefs. For this reason they are fairly tolerant of poor water quality high nitrates, phosphates an dissolved organics.
While sometimes called “soft corals,” zoanthids are different from the true soft and leather corals. Soft and leather corals are octocorals with eight tentacles per polyp instead of six. While zoanthids are related to stony or “true” corals that possess hard skeletons, zoanthids do not have a skeleton. Some zoanthids are solitary animals with a single polyp attached to a rock or shell. Other zoanthids are connected by runners called stolons, and still others are embedded in a tissue matrix or mat. This tissue matrix is called a coenenchyme. Nearly all of the ones commonly kept in the aquarium reproduce quickly through budding at the base of the polyp.
Some zoanthids create mucus that contains a toxin called palytoxin, which is one of the most deadly marine toxins. This is why it is essential to wear gloves when handling zoanthids, especially zoanthids from the family zoanthidae (Zoanthus, Palythoa and Protopalythoa).
Zoanthids harbour microscopic, single-celled symbiotic algae (zooxanthallae) within their bodies. The algae undergo photosynthesis to produce food from sunlight. The food produced is shared with the host, which in return provides the algae with shelter and minerals. Zoanthids may also feed on bacteria, algae and dissolved substances in the water. There are also reports that they may capture edible food bits from the water, while others report that they do not capture plankton.