Sea anemones are predatory fish, which live in the ocean, although they are named for the land flower of the same name.
Sea anemones are somewhat like a small bag, which is attached the bottom of the ocean by a foot, and have a large body that is shaped like a column, and ends in a mouth.
The mouth is in the center of what is known as the oral disk, and has tentacles all around it.
They serve the anemone as defensive measures and also to gather food, which in the anemones case is live prey.
The anemone has also what are called nematocysts, which contain a small bottle like structure of poison. When a specific hair at the end of the fish is touched, this is the trigger for an explosion of the gland which injects its toxins into the prey or predator.
The toxin they inject is a conglomerate of toxic substances including those which paralyze, called neurotoxins. They then capture their prey, and move it to the mouth for ingestion.
Only a few fish and people are able to withstand the sting of the anemone. Strangely enough, Nemo can. Clownfish are immune to an anemone.
The inside of an anemone is fairly simple and straightforward. There ar very few functional parts in truth, including a gastro vascular cavity which doubles as a stomach, and a single opening to the outside of the animal. In fact, the mouth and anus are the same. Waste is sent out through the mouth opening and food is taken in there.
Anemones can range in size from half an inch to more than 6 feet in diameter. They may have as few as ten or twenty tentacles, to as many as several hundred.
Sea anemones can not swim freely at any point in their lives. They are attached as eggs to the bottom and remain there for most of their life.
Unlike other cnidarians, anemones (and other anthozoans) entirely lack the free-swimming medusa stage of the life cycle: the polyp produces eggs and sperm, and the fertilized egg develops into a planula that develops directly into another polyp.
Sea anemones, unlike some species like this one, have separate sexes. The male will release sperm which in turn causes the female to release eggs and they are fertilized. They egg and sperm are both sent out through the mouth as well.
The fertile eggs become a planula, which will settle to the sea floor and become a single anemone.
Anemones may also split in half to reproduce without sexual contact.
Find out more about the Sea Anemone over at Wikipedia »