Brittle Star

Environment

Reef aquarium of at least 100 liters. Brittle stars appreciate a mature tank with sandy or mixed substrate (sand + live rock) where they can hide during the day. They take refuge in rock crevices, leaving only their arms protruding to capture food. Temperature 23-26°C, pH 8.0-8.4, salinity 1.023-1.025 (33-36 g/L), calcium 400-450 mg/L. Stable parameters essential. Lighting: tolerate intense lighting well but are mainly active at night or in dim light.

Feeding

Detritivore and opportunistic omnivore. Feeds on detritus, leftover food, small dead organisms, microalgae and plankton. In aquarium, occasionally provide pieces of fish flesh, mussels, brine shrimp or finely chopped frozen foods. They capture particles with their arms. Be careful not to overfeed the aquarium: brittle stars are content with leftovers and supplement their diet by sifting through the substrate.

Health & common diseases

Brittle stars are sensitive to salinity fluctuations and pollution from heavy metals (copper in medications). Watch for arm loss without regeneration, bleaching or lesions on the central disc, signs of stress or bacterial infection. Maintain stable water with low nitrates (<20 mg/L) and avoid any copper treatment. Slow acclimation (drip method) during introduction is essential to prevent osmotic shock.

Tips & tankmates

Excellent cohabitation with all peaceful reef fish and invertebrates. Brittle stars are harmless and shy. Beware of potential predators: large pufferfish, triggerfish or certain wrasses may attack their arms. Arms regenerate but this weakens the animal. Handle with care: arms are fragile and break easily. Never expose them to air during transfers. Excellent helpers for keeping sand clean and oxygenated. Compatible with most corals. Hardy species, perfect for the reef cleanup crew (CUC).

Sources

• World Register of Marine Species (WoRMS)
• Reef Builders - Brittle Stars Care
• Advanced Aquarist