Soft Coral
You don't normally associate Sydney with Coral. However you would be surprised how much healthy Coral there is in Sydney - especially the Soft Coral pictured here.
In certain locations which are exposed to high current there are stunning fields of it that go on for as far as the eye can see.
Although it looks a field of flowers in bloom, each Coral is actually a colony of animals each hungrily munching away at particles passing by.