Long-spined Sea Urchin

Environment

Reef aquarium minimum 200 liters with rocky décor offering hiding places and overhangs. Sandy substrate appreciated. Stable marine water: 24-28 °C, pH 8.0-8.4, density 1.023-1.026, calcium 400-450 mg/L, KH 8-12 °dKH. Moderate to strong water flow. Lighting not very important for the animal itself. Stability of parameters essential, sensitive to high nitrates (< 20 mg/L recommended).

Feeding

Herbivore/detritivore. Feeds on encrusting algae, filamentous algae and biofilm on rocks and glass. Supplement with spirulina pellets, attached dried nori, or blanched vegetables (spinach, zucchini). Feed 2-3 times per week if algae insufficient in the tank. Active mainly at night.

Health & common diseases

The long-spined sea urchin is sensitive to sudden salinity variations and thermal shocks which can cause spine loss or test disintegration. Poor water quality (high nitrates, phosphates) weakens its immune system and promotes bacterial infections visible by white spots or discoloration of the test. Prevention relies on slow acclimation (drip method over 2-3 hours), stable water with optimal reef parameters, and sufficient calcium supply for maintaining its calcareous skeleton. Avoid any contact with copper (lethal for echinoderms) and handle with care to avoid damaging the fragile spines.

Tips & tankmates

**WARNING**: highly venomous spines, painful sting that can cause allergic reactions. Handle only with caution (thick gloves, container). May knock over corals and small décor elements during its nocturnal movements: secure rockwork well. Peaceful cohabitation with most reef fish and invertebrates, avoid large competing detritivore fish (Acanthurus, triggerfish). Avoid any contact with children. Respect drip acclimation (1-2h minimum) as very sensitive to salinity and parameter variations.

Sources

• World Register of Marine Species (WoRMS)
• SeaLifeBase
• Reef Builders - Guide des invertébrés récifaux