Common Black Sea Urchin

The Common Black Sea Urchin (Diadema setosum), also known as the Black Longspine Urchin, is a marine invertebrate recognized for its distinctive black coloration and long, slender spines. In aquarium settings, it serves as an effective algae grazer, contributing to the maintenance of a balanced and healthy environment.

Essential Information:

• Common Names: Black Longspine Urchin, Black Sea Urchin
• Scientific Name: Diadema setosum
• Family: Diadematidae
• Origin/Habitat: Native to the Indo-Pacific region, commonly found in coral reef ecosystems.
• Maximum Size: Up to 8 inches (20 cm) in diameter.
• Lifespan: Typically 5 to 10 years.
• Level of Difficulty: Moderate; requires stable water conditions and appropriate tank mates.
• Reef Safe: Generally considered reef-safe, but caution is advised with certain corals.

Appearance & Physical Traits:

• Coloration & Pattern: Black body with long, slender spines; some individuals may exhibit iridescent blue spots.
• Body Shape & Structure: Globular body covered with movable spines; mouth located on the underside.

Habitat & Environmental Needs:

• Minimum Tank Size: At least 30 gallons (114 liters) to provide adequate space.
• Water Temperature: Maintain between 72°F and 78°F (22°C to 25°C).
• pH Level: Keep between 8.1 and 8.4.
• Specific Gravity: Optimal range is 1.023 to 1.025.
• Aquascape: Provide stable rockwork or substrate for attachment; ensure the urchin is securely positioned to prevent movement.

Diet & Feeding:

• Diet Type: Herbivorous
• Preferred Foods: Algae, including macroalgae and detritus.
• Feeding Frequency: In a well-established tank with sufficient algae, supplemental feeding may not be necessary. If algae is lacking, provide dried algae sheets, spinach, or other greens.

Behavior & Compatibility:

• Temperament: Peaceful and non-aggressive.
• Social Behavior: Solitary; does not require companions but can coexist with other peaceful tank inhabitants.
• Tank Mate Compatibility: Compatible with most reef-safe fish and invertebrates. Avoid housing with predatory species that may harm them.
• Activity Level: Primarily nocturnal; may be more active during the night.

Care Considerations & Additional Notes:

• Ease of Care: Moderate; requires stable water parameters and appropriate tank mates.
• Special Requirements: Ensure high-quality water with low nutrient levels to prevent excessive algae growth.
• Breeding Info: Reproduction in captivity is uncommon; they are broadcast spawners, releasing eggs and sperm into the water column.
• Additional Notes: Regular monitoring of water quality is essential. Ensure there is sufficient algae or be prepared to provide supplemental feeding.