Pink and Black Sea Cucumber

The pink and black sea cucumber is a soft-bodied echinoderm, black on the back and pink–red on the belly, that reaches 20–30 cm. It swallows sand using short tentacles around its mouth, digests the organic matter in it and releases clean sand again; in this way it stirs the sand bed and keeps it clean. Warning: The tissues of sea cucumbers contain toxic saponin-type substances. If it is sucked into a pump and torn apart, picked at by fish or dies, these substances are released into the water and can cause mass deaths of fish. Those on the market are wild-collected.

• 200 liters or more; a large, mature sand bed of fine sand at least 5 cm deep.
• Salinity specific gravity 1.024–1.026, pH 8.1–8.4, temperature 24–27°C; salinity should be stable.
• All pump and filter intakes should be covered with sponges; activated carbon should be kept on hand for emergencies.
• Reef safe; it does not touch corals. It should be acclimated by the drip method for at least 2 hours; copper-based medications are lethal.

It feeds on detritus, biofilm and microorganisms in the sand. If the sand bed is insufficient, it can be supplemented with sinking granules pushed into the sand; a thinning body is a sign of starvation.

Slow and peaceful; it roams the sand day and night and sometimes climbs the glass. It contracts under stress; a sick or injured individual should be removed immediately.

Good companions: clownfish, gobies, cardinalfish; shrimp, snails.

Avoid: pufferfish, triggerfish, butterflyfish and angelfish that might pick at it; unprotected pump intakes; other sand sifters that would share the sand bed.