Coral Predators: The Animals That Eat Coral Reefs

Coral reefs are not just habitat — they are food. A diverse array of organisms consume coral tissue, mucus, or skeleton, shaping reef structure and ecology.

Specialist Corallivores (Obligate Coral Eaters)

• Butterflyfish (Chaetodontidae): ~30 species — protrusible mouths, fine teeth nip polyps. Chaetodon trifascialis eats only Acropora.
• Parrotfish (Scaridae): Excavators (Bolbometopon, Chlorurus) bite deep, scrapers (Scarus) graze surface — bioerosion agents, produce sand.
• Crown-of-thorns starfish (Acanthaster planci): Population outbreaks devour entire reefs — major threat in Indo-Pacific.
• Coralliophila snails: Ectoparasitic — suck tissue from Acropora, Porites.
• Harpilodidae (coral gall crabs): Live in galls, feed on mucus/tissue.

Generalist Feeders (Opportunistic)

• Surgeonfish (Acanthuridae): Graze algae but ingest coral incidentally.
• Triggerfish (Balistidae): Strong jaws — bite branching corals, eat Coralliophila snails.
• Angelfish (Pomacanthidae): Sponge/tunicate feeders — nip coral.
• Pufferfish, filefish, wrasses: Occasional coral bites.
• Sea urchins (Diadema, Echinometra): Scrape algae, erode skeleton — key bioeroders.
• Chitons (Polyplacophora): Rasping radula on coral rock.

Megafauna (Rare but Impactful)

• Hawksbill turtles: Spongivores but bite coral accessing prey.
• Dolphins: Rarely documented rubbing/biting coral — possibly medicinal/play.
• Sharks, rays: Incidental during foraging; no obligate corallivory.

Ecological Roles

• Bioerosion: Parrotfish, urchins, sponges, worms — recycle CaCO₃, create sediment, complexity.
• Population control: Predators on corallivores (e.g., triton snail eats COTS) maintain balance.
• Disease vectors: Some corallivores transmit coral pathogens.
• Phase shifts: Overfishing herbivores + nutrient enrichment → algal dominance; COTS outbreaks → coral loss.

Conservation Note

Corallivory is natural — reefs evolved with it. Human-driven imbalances (overfishing predators, nutrient pollution, warming) turn natural predation into destruction. Protecting predator populations and water quality is key to reef resilience.