Black Longspine Urchin (Diadema Setosum)

Care Level : Easy

Temperament : Peaceful

Color : Black, Red, White

Diet : Herbivore

Reef Compatible : Yes

Water Conditions : 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.023-1.025

Max. Size : 10"

Venomous : Yes

Origin : Indo-Pacific

Family : Diadematidae

Supplements : Calcium, Iodine, Trace Elements

Black Longspine Urchin (Diadema Setosum) is a species of long-spined sea urchin belonging to the family Diadematidae. The species can be found throughout the Indo-Pacific region, from Australia and Africa to Japan and the Red Sea. 

It is a typical sea urchin, with extremely long, hollow spines that are mildly venomous. 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.

Diadema Setosum differs from other Diadema with five, characteristic white dots that can be found on its body. The Black Longspine Urchin has a body which is predominately black with a red eyespot in the center. The spines on these urchins are long, thin and completely black. They are a very delicate looking urchin, which are actually very capable of protecting itself.

This species thrives best in tanks with plenty of live rock to explore and feed off of. Provide an aquarium with ample hiding places and room to roam. Being a nocturnal creature, the Black Longspine Urchin will hide during the day and only come out at night to forage for food such as algae and seaweed. These urchins are an excellent algae controller for an aggressive aquarium where other invertebrates would be eaten. When approached by a fish, these urchins will sense their presence, and will defend itself by directing its spines towards its offender.

It is very sensitive to high levels of copper-based medications and will not tolerate high nitrate levels. If it begins to shed its spines, it is a sign of very poor water quality.

Although the urchins will get most of their food from the tank, this might not be enough, especially if the tank is not that large or you have other algae eaters. Supplement the diet with sinking algae-based pellets and occasional pieces of meaty foods, such as shrimp.

Size: Small: 1-1/2" to 2"; Medium: 2" to 3" Large: 3" to 4"