ZOANTHIDS (Zoanthus) Cuvier, 1800
The Sea Mat zoanthids have a few species, including Z. sociatus (Sea Mat) and Z. pulchellus (Zoanthid Button Polyps), which are found here in the tropical Atlantic. The species in the Zoanthid genus have the ability to change color to a darker or lighter shade depending on the light. This makes them less likely to bleach out. They can be found in various reef environments including being out in the open during low tide! This indicates a need for bright light.
Even though they use good amount of light, they also need to feed from the water column to live, so pristine water conditions may not be the best environments. They can be feed zooplankton, but may not respond, since they fed mostly on dissolved organic waste, algae, and bacteria.
Colors can be a wide variety of blues, greens, yellow, sometimes orange, and combinations of some or all 3. They typically have contrasting skirts, discs, and centers! 10K really makes them POP! Their polyps are rarely bigger than 1/2."
Sometimes a Sea Mat colony will feel the need to "cleanse" itself and close up for a week. Don't worry, they are fine. They reproduce by budding from the base of the parent colony. Wash your hands after handling. Although they do not have the dangerous palytoxin in their mucus, that the Palythoa zoanthids do, it is a good habit.
Here are a few identification features:
Zoanthus sociatus have polyps with 30 short tentacles each, that are green to turquoise. Their mats are not symmetrical, and when closed are tightly crowded together. They feed on detritus, but not zooplankton.
Zoanthus pulchellus has a very dense mat that crowds the zoas together. Can't tell you the polyp count on that one but they are short and blunt.
Light: Moderate & High
PH: 8.0 to 8.3
Minimum Tank size: ALL sizes