Reefs host thousands of fish species, including iconic residents like clownfish (symbiotic with anemones), parrotfish (algae grazers with beak-like jaws), butterflyfish (coral polyp feeders), surgeonfish (razor-sharp tail spines), wrasses (cleaners and predators), groupers and snappers (apex predators), plus various sharks and rays.
The reef framework itself is built by stony corals, accompanied by soft corals, sea anemones, sponges, crustaceans (shrimp, crabs, lobsters), mollusks (giant clams, nudibranchs, octopuses), echinoderms (sea stars, urchins, sea cucumbers, crinoids), and worms (Christmas tree worms, feather dusters).
Reptiles: Sea turtles (hawksbill, green, loggerhead) forage and rest on reefs; marine iguanas (Galápagos) feed on algae.
Mammals: Dolphins hunt near reefs; dugongs and manatees graze seagrass beds adjacent to reef systems; whales may pass through during migrations.
This diversity thrives on intricate relationships: cleaning stations, predator-prey dynamics, symbiotic partnerships, and niche specialization—all built upon the coral's calcium carbonate foundation.