Long-spined sea urchin
Diadema setosum
The long-spined sea urchin is a reef invertebrate recognizable by its very long, thin black spines (up to 30 cm). An excellent detritivore and algae grazer, it plays a useful role in the reef aquarium but its venomous spines require caution during maintenance. Primarily nocturnal, it hides during the day in the rocks.
Parameters
- Water type
- Saltwater
- Min volume
- 200 L
- Temperature
- 24–28 °C
- pH
- 8–8.4
- Carbonate hardness (KH)
- 8–12 °KH
- Salinity
- 33–36 g/L
- Calcium
- 400–450 mg/L
- Adult size
- 8 cm
- Lifespan
- 4 years
- Diet
- herbivore
- Temperament
- paisible
- Difficulty
- modéré
Environment
Reef aquarium minimum 200 liters with rocky décor offering hiding places and overhangs. Sandy substrate appreciated. Stable saltwater: 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 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, dried nori attached, or blanched vegetables (spinach, zucchini). Feed 2-3 times per week if algae insufficient in the tank. Active mainly at night.
Tips & tankmates
**WARNING**: highly venomous spines, painful sting can cause allergic reactions. Handle only with caution (thick gloves, container). May knock over corals and small décor elements during 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 variations in salinity and parameters.
Sources
- World Register of Marine Species (WoRMS)
- SeaLifeBase
- Reef Builders - Guide des invertébrés récifaux
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