Fire urchin

Asthenosoma varium · The fire urchin is a large, venomous sea urchin that lives on sand and rubble sea bottoms in the Indo-Pacific.

Also called Variable fire urchin, Pacific fire urchin, Electric sea urchin, Elusive sea urchin.

Fire urchin
Photo: Jason Marks, CC BY-SA 3.0
Fire urchin
Photo: Candace Pratt, CC BY-SA 3.0
Fire urchin
Photo: prilfish, CC BY 2.0

Taxonomy

KingdomAnimalia
PhylumEchinodermata
ClassEchinoidea
OrderEchinothurioida
FamilyEchinothuriidae
GenusAsthenosoma
SpeciesAsthenosoma varium

Where it lives

Indo-Pacific coral reefs from the eastern Indian Ocean to Japan and New Caledonia, down to 167 m.

Fun facts

  • A fire urchin's sting can hurt for as long as several hours.
  • Its shell is flexible because its plates overlap like roof tiles instead of being rigidly joined like most sea urchins.
  • The spines have toxin-filled capsules that work like hypodermic syringes.
  • Small fish like Siphamia tubifer shelter among the urchin's toxic spines for protection, as do certain cephalopods.

Play it

The Fire urchin was the creature in a regional daily on November 8, 2026. Can you identify tomorrow's from its photos? Every day brings a new creature to place from kingdom to genus, map and name.

Play today's creature or replay a past daily

Facts and taxonomy adapted from Wikipedia (CC BY-SA 4.0).