Black Sea Cucumber (Holothuria atra)

The Black Sea Cucumber is a premier substrate cleaner that acts as a natural biological filter for marine aquariums. Coated in a protective layer of mucus that frequently traps a fine dusting of sand for camouflage, this slow-moving detritivore relentlessly sifts through the upper layers of the sand bed. By consuming organic waste, decaying matter, and microfilm, it breaks down trapped nutrients and actively prevents substrate compaction. They are peaceful inhabitants that thrive best in mature systems with deep, well-established sand beds.