Sea anemones are animals which are well known for their relationships with clownfishes which are also known as anemonefishes. Worldwide, there are almost 1000 species of sea anemones, in waters which range from cold to warm, and from the shoreline to great depths. Of these only ten are host to anemonefishes. Two, Entacmaea quadricolor and Heteractis crispa are found at Julian Rocks. There are 27 species of the fish genus Amphiprion, all of these are symbiotic with anemones. Three of these, Amphiprion akindynos, Amphiprion latezonatus and Amphiprion perideraion are found at Julian Rocks. The relationships between species of anemones and species of anemonefish are quite restricted with some fish living with only one host and vice-versa although relationships of several to several are more common. Dascyllus trimaculatus often live with anemones when they are small, but are not dependent on them and move away when they are older. Some shrimps and crabs also live closely with anemones.

Anemones are known to have lived for several decades in commercial aquaria and it likely that they are long lived in the wild although this is difficult to determine. Host anemones reproduce sexually although the detailsl are not well understood. Some, such as Entacmaea quadricolor, can divide to form cloned groups, which look like a singe anemone.

Single celled golden-brown algae known as zooxanthellae live within the cells of the tentacles and oral disc of many anemones. These plants photosynthesise to produce sugars for their own needs, but also supply their host anemones. Anemones also capture food such as small crustaceans. Tentacles are armed with nematocysts which spear and poison prey. Resident anemonefish are not subject to attack - for reasons which are not fully understood. For further information refer to "Field Guide to Anemonefishes and Their Host Sea Anemones"

more images of anemones and anemonefishes