Despite being capable of causing painful stings when stepped upon, the urchin is only slightly venomous and does not pose a serious threat to humans.

D. setosum can be distinguished from other species in the genus Diadema by the presence of five white spots on the animal's test, strategically located between the urchin's ambulacral grooves.

Its range stretches throughout the Indo-Pacific basin including Malaysia,[7] longitudinally from the Red Sea and then eastward to the Australian coast.

Latitudinally, the species can be found as far north as Japan and its range extends as far south as the southern tip of the African east coast.

The discovery and subsequent collection of these individuals makes D. setosum the first invasive Erythrean sea urchin in the Mediterranean.

[3] Diadema setosum is commonly associated with coral reefs, but is also found on sand flats and in seagrass beds.

[6] In Hong Kong, Diadema setosum is omnipresent in rocky reefs, with a population density of up to one individual per 3.4m2.

Genetic analysis of the Diadema have placed D. setosum at a basal branch on a cladogram, having it as the sister group to all the other remaining members of the genus.

[13] Morphological analysis confirms this conclusion, adding weight to the concept of D. setosum being the most basal of the Diadema and possibly the oldest extant species in the genus.

[14] In terms of behavior, D. setosum has been observed to be able to avoid danger by rapidly inverting its body and "running" on the tips of its longest spines.

It is also worth noting that this particular variety has some of the very best vision observed among sea urchins and will regularly redirect spines toward passing fish as a defense mechanism.