Orange-centered Zooanthids
(Phylum Cnidaria, Class Anthozoa, Order Zooanthidae. See Overview of Cnidarian Diversity)
Many of the zooanthids are extremely colorful. This type is particularly spectacular, with bright orange polyp centers and fluorescent green tentacles that fluoresce golden yellow when illuminated by just the blue actinic lights (e.g. during the simulated dawn and dusk periods in morning and evening)
(click for photo of fluorescing corals)
About zooanthids:
Zooanthids are anemone-like anthozoans that usually grow in colonies. In some species the polyps separate from each other almost completely after budding off from each other, while in other species the polyps are all interconnected by a continuous mat of tough, rubbery/leathery living tissue.
Like nearly all of the other cnidarian species in our aquaria, these zooanthids depend on the products of photosysnthesis from their zooxanthellae for most of their nutrition. (zooxanthallae are symbiotic algae that live in their tissues)