Florent's Guide To The

Tropical Pacific Reefs

Blue-Black Urchin
Echinothrix diadema
Blue-Black Urchin
Category: Sea Urchins
Scientific Name: Echinothrix diadema
Size: 4 to 8 in. (10 to 20 cm)  
Depth: 3-30 ft. (1-10 m)
Distribution: Indo-Pacific, Hawaii
Echinodermata (Phylum)
└Echinozoa (Subphylum)
 └Echinoidea (Class)
  └Diadematoida (Order)
   └Diadematidae (Family)
    └Echinothrix (Genus)

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© 2025 Florent Charpin