Common name: Pencil Urchins

Cidaroida, commonly known as Pencil Urchins, is an order of sea urchins characterized by their thick, blunt spines that resemble pencils. These urchins are found in various marine environments and are known for their hardy nature, making them suitable for reef aquariums. They play a crucial role in the ecosystem by grazing on algae, which helps prevent overgrowth and maintain the balance in the tank. Pencil Urchins are generally peaceful and can coexist with a variety of tank mates. However, their spines can be sharp, so careful handling is advised.

1. 
   Common name: Pencil Urchin

   Scientific name: Eucidaris metularia
2. 
   Common name: slate pencil urchin

   Scientific name: Eucidaris tribuloides
3. 
   Common name: Slate Pencil Urchin

   Scientific name: Goniocidaris tubaria
4. 
   Common name: pencil urchin

   Scientific name: Phyllacanthus imperialis
5. Common name: Cidaroid Sea Urchin

   Scientific name: Plococidaris verticillata
6. Common name: Crown-spined Pencil Urchin

   Scientific name: Prionocidaris baculosa
7. 
   Common name: Pencil Sea Urchin

   Scientific name: Prionocidaris bispinosa
8. 
   Common name: red lance urchin

   Scientific name: Stylocidaris affinis