A sea anemone is a water dwelling animal and is predatory by nature. They can successfully be kept I the home aquarium if water conditions and lighting are sufficient.
A sea anemone is a polyp that is attached to the bottom by a sticky foot called a basal disc. A sea anemone can grow as large as two meters. There are may different species of anemone and some are capable of floating upside down in the water. They do not attach to the bottom and have a gas chamber that allows them to float.
The mouth also happens to be the anus of the sea anemone and is situated in the middle of the oral disc. This is surrounded by many tentacles armed with cnidocytes which are cells that function as a defensive mechanism as well as allowing the anemone to catch prey. Each tentacle is filled with toxins and when the tentacle is touched it triggers an automatic explosion of toxins. It acts like a harpoon and injects a dose of venom into its aggressor or prey. This gives an anemone a sticky feeling when touched. Our skin is too hard for the venom to penetrate so we are able to handle the anemone without any adverse effect.
The digestive system is formed of a gastrovascular cavity with a single opening to the outside. This functions as the mouth and anus. Undigested food as well as waste is secreted through this opening. An anemone will generally stay in the same place unless conditions become unfavourable, or if a predator attacks them. When this happens the anemone can flex its body and swim to a new location. Some sea anemone are hermaphrodites whilst others are either male or female.
Anemone are farmed in increasing large numbers to be shipped across the world. This is reported to have a significant impact on some populations as well as having an adverse effect on anemone shrimp. Anemone are also sold for a lot more that an anemone fish creating a lucrative business from their sale.