Astropyga radiata is a large urchin with a test diameter of up to 20 cm (8 in), flattened or slightly concave on the aboral (upper) side.

After fertilisation, the larvae are planktonic and develop through several stages before settling on the seabed and undergoing metamorphosis into a juvenile urchin.

These include the commensal shrimps Periclimenes hirsutus and Stegopontonia commensalis and the crab Zebrida adamsii.

[2] Although not deadly to humans, these urchin's quills are quite venomous; capable of inflicting painful wounds.

[4] However, being a rather large and brightly colored species of urchin, it is relatively visible to divers, making injuries by accidentally stepping on one comparatively rare.

It goes by the name of Roter (Diadem)Seeigel in German, Riccio rosso in Italian, Falso erizo de fuego in Spanish, and Oursin rouge in French.