Sea Urchin
Category: Saltwater Reef Fish
About
Sea urchins are small, spiny, globular echinoderms found on the seabed of oceans all over the world. They play important roles in marine ecosystems.Scientific Name
Class: EchinoideaHabitat
Found in shallow coastal waters, rocky seabeds, coral reefs, and ocean floors at various depths.Conservation
Most species are not endangered, but overharvesting (for food or aquariums), pollution, and reef destruction pose threats in some areas.Lifespan
Varies by species; many live 4 to 30 years depending on environment and predation.Fun Fact
Sea urchins have a unique mouth structure called "Aristotle’s lantern" which they use to scrape algae from rocks.Diet
Mostly herbivorous – feeds on algae and detritus. Some species are omnivorous and eat small invertebrates.Average Size
Ranges from a few centimeters to up to 10–15 cm in diameter.Location / Placement info
Displayed in the Coastal Reef Exhibit, near the Ocean-View TunnelFAQ
What is the lifespan of a Sea Urchin?
Depending on the species, they can live up to 30 years in the wild.
What do they eat?
They are herbivores or omnivores, eating algae, seagrass, and detritus.
Are Sea Urchins aggressive?
No, but their spines can injure if touched or stepped on.
What is the ideal tank size for captive Sea Urchins?
A minimum of 30 gallons, with live rock and stable marine conditions.
Do they need a specific environment?
Yes, they need stable salinity, pH, low nitrates, and plenty of surfaces to graze.
How big do Sea Urchins grow?
Most species grow up to 3–4 inches (7–10 cm) across, but some can be larger.
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