Arctic Green Sea Urchin (Strongylocentrotus droebachiensis)

Strongylocentrotus droebachiensis is a cold-water sea urchin that does best in stable, well-filtered marine systems. They are relatively hardy compared to other echinoderms. They require constant feeding which is something to be aware of. A cycled tank with strong biological filtration is essential. These urchins do best in tanks with a large surface area, as they spend most of their time grazing along the bottom. A sand or fine gravel substrate is preferred. Water flow should be moderate, not turbulent. Strong currents can damage tube feet and make grazing difficult. Strongylocentrotus droebachiensis consumes microalgae in its younger, larval, and juvenile stages, while adults graze macroalgae and microalgal films on rocks. Live microalgae such as Tetraselmis chuii, and Nannochloropsis sp., are available. Live and dried macroalgae are suitable. Weekly water changes and removal of uneaten food are important to prevent ammonia buildup. They tolerate cooler temperatures better than warm, so a chilled system is ideal if you’re planning long-term culture.