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Long-Spined Urchin (Diadema setosum)

Find Long-Spined Urchin across reef-livestock retailers and from fellow hobbyists on ReefDock. Compare sources, check live pricing where available, and review source-tank parameters on Reef-Trak-verified invertebrate listings before you buy.

Long-Spined Urchin
Photo: (c) Patrick Randall, some rights reserved (CC BY-NC-SA) · cc-by-nc-sa
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Where to buy Long-Spined Urchin

ReefDock searches the following reef retailers for this invertebrate. Click through to see the live price.

  • Saltwaterfish

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    Search Saltwaterfish
  • Amazon

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    Search Amazon
  • Petco

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About Long-Spined Urchin

Black or dark purple spherical body covered entirely with long, slender spines that may reach 6 inches in length. Distinctive tube feet project between spines; body diameter typically 3–4 inches.

Key facts

Origin
Indo-Pacific from the Red Sea through Southeast Asia to the Hawaiian Islands and Central Pacific reefs.
Type
Cleanup
Max Size
12
Water Parameters
Temperature: 72-78°F pH: 8.1-8.3 Salinity: 1.023-1.025
Family
Diadematidae
Min tank size
55 gallons
Diet Details
Primarily herbivorous, grazing on algae. Supplement with macroalgae (kelp, nori) and occasional protein-rich foods like spirulina or frozen phytoplankton in mature tanks with limited natural algae.
Appearance Description
Black or dark purple spherical body covered entirely with long, slender spines that may reach 6 inches in length. Distinctive tube feet project between spines; body diameter typically 3–4 inches.
Compatibility
Diadema urchins are generally compatible with most fish and invertebrates, but their long spines can damage corals and injure delicate tank-mates. They are territorial and may harass smaller creatures.
Notes
Excellent for controlling hair algae. Active during day and night. Temperature range 72-78°F. Needs stable parameters. May knock over unsecured frags. Good for both sand and rock surfaces. Spines can be sharp, handle with care.
Care Level
Moderate
Category
Urchin

Looking for a hobbyist seller?

ReefDock's marketplace lets reef-keepers sell invertebrates directly to other reef-keepers with Stripe-secured checkout and live-arrival photo confirmation. Browse current invertebrates listings on ReefDock, or list your own.

Verify the source tank before you buy

ReefDock is the sister app to Reef Trak. Sellers who maintain a Reef Trak tank log can publish source-tank parameters on eligible invertebrate listings — so you can see the conditions a invertebrate was raised in before you buy. Log this invertebrate on Reef Trak.

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