Urchins

Few animals command the visual interest that sea urchins can in an aquarium. While most species are excellent algae eaters and make welcome additions to a cleanup crew, urchins can make interesting display animals in their own right. Some varieties display brilliant colors, while others can form fascinating associations with certain fish and crab species, not unlike an anemone with clownfish. Urchins tend to be more sensitive to quick changes in water chemistry than other cleanup crew invertebrates, and should be maintained in well established systems with good water quality parameters. They will be healthiest with low nitrate, zero/low phosphate, 8-11dKH, and 380-450ppm calcium. It is important to ensure there is enough algae in the aquarium to feed an urchin long term, otherwise supplemental foods, such as dried seaweed/nori, need to be added. Some of the most common varieties available include: Pincushion, Longspine, Tuxedo, Halloween, Fire, and Pencil Urchins.