Actini

Actini refers to a group of marine invertebrates belonging to the phylum Cnidaria, class Anthozoa, and subclass Hexacorallia. These are commonly known as sea anemones. Sea anemones are sessile polyps, meaning they are attached to a substrate, typically the seabed, rocks, or shells. They are characterized by a cylindrical body topped with a oral disc containing a mouth and typically surrounded by a ring of stinging tentacles. These tentacles are armed with nematocysts, specialized cells used for capturing prey and for defense.

Sea anemones exhibit a wide range of diversity in size, color, and form. They are predatory, feeding on small fish, crustaceans, and plankton that come into contact with their tentacles. Some species have symbiotic relationships with other marine organisms, such as clownfish, which gain protection from the anemone's stinging cells by living among its tentacles. In return, the clownfish may help to clean the anemone or lure prey.

Reproduction in sea anemones can be asexual, through budding or pedal laceration, or sexual, involving the release of sperm and eggs into the water column. The fertilized eggs develop into free-swimming larvae that eventually settle and metamorphose into new polyps. Sea anemones play a role in marine ecosystems as both predators and prey, and their presence can be an indicator of a healthy marine environment.