Common name: Sea urchin

General information

The Long-spined Sea Urchin, Diadema savignyi, is a striking invertebrate commonly found in the tropical Indo-Pacific region. It is known for its long, thin spines that can reach up to 30 centimeters in length, which are banded with contrasting colors of black and white or cream. This sea urchin is nocturnal and tends to hide in crevices during the day.

Care

Diadema savignyi requires a well-established aquarium with plenty of live rock and hiding places. It is important to handle this urchin with care due to its sharp spines, which can inflict painful wounds. The urchin is an excellent algae grazer and will help keep the tank clean by consuming unwanted algae. However, it may also inadvertently damage or consume small sessile invertebrates.

Reproduction

In the wild, Diadema savignyi reproduces by releasing gametes into the water column, a process known as broadcast spawning. In the aquarium, breeding is less common but can occur if conditions are favorable. The larvae are planktonic before settling and developing into juvenile urchins.

Symbiosis

While not hosting symbiotic relationships as iconic as those of clownfish and anemones, Diadema savignyi plays a crucial role in the reef ecosystem by controlling algae growth, which can otherwise overwhelm coral reefs and disrupt the balance of the ecosystem.

Habitat

This species is typically found in shallow reef environments, often in areas with strong water movement. It is widespread throughout the Indo-Pacific, from the Red Sea and East Africa to the central Pacific Ocean.