Actiniidae

Actiniidae is the largest family of sea anemones. Members of this family are typically those anemone found along shorelines.

Actiniidae can be identified from other anemone by the number of tentacles. Actiniidae have only one tentacle per space between mesenteries and the mouth of the anemone. Mesenteries are double layers of peritoneum connecting various components of the abdominal cavity.

Another defining characteristic of this family, is that they do not form symbiotic relationships with fish, with the exception of the "Bubble-tip anemone" or Entacmaea quidricolor. Some forms of anemone protect fish from predators in return for food. Meaning that they feed off of the food particulates that fall off the fish, or are cleaned off by the fish.

Anatomy
Most anemone, including actiniidae, have a tubular body (radial symmetry). At one end of this body is a circular disc which acts as the anemones mouth. This mouth is surrounded my many tube like tentacles. These tentacles are used similar to how humans use fingers. The anemone captures food with these tentacles and brings it to the hole at the center of its circular disc, which holds its mouth. The anemones mouth also acts as the mode of excretion for wastes from the anemones diet. The anemones brilliantly colored tentacles often come with stingers at the end for stunning prey (nematocysts), and for personal protection from predators.

Reproduction
Actiniidae are not different from other families under actinaria when it comes to reproduction. They share the same forms of reproduction as all the other anemone. The first is sexual reproduction, which divides the anemone up by male and female. The male let sperm into the gastric cavity of the female. Then the developed young are discharged through the only opening, the mouth, of the female anemone.

The anemone also has two known forms of asexual reproduction. Budding, the breaking off of one organism from its parent organism. With budding the offspring are completely identical. Fission, which is a complicated process of cell cloning deep within the anemone.

Ecology
A recent study by the United Kingdom's National Oceanography Center (2005) has reported that the melting of the ice caps at the top of the globe (Greenland, Arctic areas) has increased the level of freshwater in north Americas oceans. This means that the ‘salinity level’ is down. This also means that when the currents bring the warmer waters around, they are not mixing properly. This is not only harmful to the anemone population, but to the weather conditions for north Americans as well.

The anemone is a very adaptive animal. An interesting pattern is appearing before scientists. The closer that the organism is to the tropics (or otherwise ‘warmer waters‘ as we know is lighter and shallower), both land and water, the more diverse they are. Meaning, the closer to the warmer waters the more anemones are different, and there are more kinds of anemones. All in all flourishing of animals in the warmer waters. This tends to lead anemones and other organisms to spontaneously create their own small ecosystems. The remoteness of the tropical regions also helps these "ecosystems" to grow in number and diversity.

There are two different habitats that anemones thrive in, mainland, and offshore. Mainland, which is closer to the land and shallower coastline seem to have more diversity, whereas the offshore bodies of water seem to diversify less. This may be due to the colder, and denser water conditions. Also to lack of light in the deeper regions.

Extras
A special kind of actiniidae is called the "bulb-tentacle" or Bubble-tip anemone. This anemone is particularly special because of its odd, bulb shaped tentacles. These "bulbs" are located at the end of each anemones tentacles. The bulb is usually white, with a red dot at the end.

A special aspect of this anemones bulb-tentacles is that it can immediately suck these oversized bulbs back into its body with the ease of an anemone with regular tube-like tentacles. This is possible because each of the bulbs is hollow inside, allowing for "easy storage" if you will. These special polyps are found in Micronesia,  Melanesia, East Africa, Red Sea, Australia, and Japan.

Related References

 * Caribbean Region Ecosystem Carrib Resource, Actiniidae and Carribean Reefs
 * Sea Anemones (Actiniaria) by Minature Reef, Actiniidae Anatomy
 * Sea Anemones Classification bu JJ Geisler
 * Actiniidae Wikipedia, Defining Characteristics of Family