Common name: Sea Urchins

Diadematoida is an order of sea urchins known for their long, thin spines that can be quite sharp and venomous in some species. Members of this order, such as the genus Diadema, are important for their role in controlling algal growth on reefs. They are generally nocturnal and can be sensitive to water quality, requiring stable conditions. Hobbyists should handle them with care due to their spines and consider their potential to reshape the reef scape by grazing on algae.

1. 
   Common name: Pale spine fire urchin

   Scientific name: Astropyga magnifica
2. 
   Common name: Blue-spotted urchin

   Scientific name: Astropyga radiata
3. 
   Common name: long-spined urchin

   Scientific name: Centrostephanus longispinus
4. 
   Common name: Long-spined Sea Urchin

   Scientific name: Centrostephanus rodgersii
5. 
   Common name: long-spined sea urchin

   Scientific name: Diadema antillarum
6. 
   Common name: Sea urchin

   Scientific name: Diadema savignyi
7. 
   Common name: black longspine urchin

   Scientific name: Diadema setosum
8. 
   Common name: banded sea urchin

   Scientific name: Echinothrix calamaris
9. 
   Common name: Diadema urchin

   Scientific name: Echinothrix diadema