Zoanthidae

Zoanthidae is a family of marine invertebrates commonly known as zoanthids or zoanthids. These cnidarians are sessile, meaning they live attached to a substrate, and are typically found in shallow, tropical marine waters. Zoanthids are colonial organisms, with many individual polyps connected by a sheet of tissue called a coenenchyme. Each polyp is relatively simple, possessing a cylindrical body topped with a ring of tentacles surrounding a central mouth. They come in a wide variety of colors and patterns, often displaying vibrant hues that make them popular in the aquarium trade.

Zoanthids are filter feeders, using their tentacles to capture plankton and other small organic particles from the water. They can also absorb dissolved organic matter directly from the water column. Many species of zoanthids have a symbiotic relationship with photosynthetic dinoflagellates called zooxanthellae, which live within their tissues. These algae provide the zoanthids with nutrients through photosynthesis, and in return, the zoanthids offer the algae protection and access to sunlight. This symbiosis contributes significantly to the coloration and nutritional needs of many zoanthid species.

Reproduction in zoanthids can occur both asexually, through budding and fragmentation of the colony, and sexually, by releasing eggs and sperm into the water. They play a role in reef ecosystems by providing habitat and food for other organisms, and by contributing to the structural complexity of the reef. Some species are known to produce potent toxins, which can be a defense mechanism against predators.