Corals

Corals, sea anemones and their relatives belong to a group of animals called Cnidarians. Coral colonies are composed of individual polyps that have six or more tentacles, each lined with stinging cells (nematocysts). There are several different kinds of corals and coral-like animals. Hard corals secrete limestone skeletons and are responsible for the creation of tropical coral reefs. Related animals - such as soft corals, gorgonians and sea pens - do not construct reefs, but are nevertheless important to reef ecology.

Reef-building corals gain energy and nutrition from symbiotic algae that live within their tissues, and that may impart a distinctive color to their hosts. Most corals grow very slowly - often only inches a year - but over a period of thousands of years they can create enormous structures such as atolls and barrier reefs.

Coral Reef, Micronesia — Coral Reef,
Micronesia

Coral Reef, Indonesia — Coral Reef,
Indonesia

Coral Reef and Jacks, New Guinea — Coral Reef and Jacks,
New Guinea

Coral Reef, New Guinea — Coral Reef,
New Guinea

Coral Reef and Fusiliers, Solomon Islands — Coral Reef and Fusiliers,
Solomon Islands

Table corals, Indonesia — Table corals,
Indonesia

Sea Pens, British Columbia — Sea Pens,
British Columbia

Cabbage Coral, Fiji — Cabbage Coral,
Fiji

Broccoli Coral, Indonesia — Broccoli Coral,
Indonesia

Soft Coral, Indonesia — Soft Coral,
Indonesia

Soft Coral, Papua New Guinea — Soft Coral,
Papua New Guinea

Sea Fan, New Guinea — Sea Fan,
New Guinea

Hard Coral, Indonesia — Hard Coral,
Indonesia

Daisy Coral, Indonesia — Daisy Coral,
Indonesia

Gorgonian Coral, Caribbean — Gorgonian Coral,
Caribbean

Black Coral, Indonesia — Black Coral,
Indonesia

Tube Coral, Red Sea — Tube Coral,
Red Sea

Wire Coral, Indonesia — Wire Coral,
Indonesia

Hard Coral, New Guinea — Hard Coral,
New Guinea

Whip Coral, New Guinea — Whip Coral,
New Guinea

Spawning Coral, New Guinea — Spawning Coral,
New Guinea

Mushroom Coral, Indonesia — Mushroom Coral,
Indonesia

Anchor Coral, Indonesia — Anchor Coral,
Indonesia

Corallimorpharians, Tasmania — Corallimorpharians,
Tasmania

Star Coral, Caribbean — Star Coral,
Caribbean

Zoanthids, Tasmania — Zoanthids,
Tasmania