Order
Common name: Sea urchins
Scientific name: Echinothurioida
Echinothurioida is an order of sea urchins known for their deep-sea habitats and long spines. Members of this order, such as the genus Asthenosoma, are often characterized by their flexible spines and ability to inflate themselves as a defense mechanism. They are not commonly kept in home aquariums due to their specialized care requirements and potential to harm other tank inhabitants with their venomous spines. However, their unique appearance and behaviors can make them a subject of interest for advanced aquarists with the capability to provide for their needs.