Long-Spine Urchin (Diadema setosum)
A dramatic black urchin with needle-like spines, this nocturnal grazer is excellent for algae control but requires careful handling due to its venomous spines.
 
Size: Up to 10 inches (25 cm) including spines
Tank Size: Minimum 75 gallons
Care Level: Moderate
Diet: Herbivore – grazes on algae, seaweed sheets
Aggression Level: Peaceful
Compatibility: Reef-safe but may knock over unsecured corals and rocks
Notes: Nocturnal; venomous spines can sting—handle with extreme care; needs stable, mature tank