Common name: Sand Dollar

General information

The Sand Dollar, scientifically known as Clypeaster humilis, is a species of flattened, burrowing sea urchins belonging to the family Clypeasteridae. These echinoderms are well-known for their distinctive, coin-like shape, which is where their common name originates. In life, they are covered with a velvety coat of tiny spines and appear brown or purplish, but when found on beaches, they are usually bleached white by the sun.

Care

Sand Dollars are filter feeders and require a well-established aquarium with a deep sand bed and stable water conditions. They are sensitive to changes in water quality and should be kept in a tank with low to moderate water flow. It's important to provide a diet of fine particulate organic matter, which they can sift from the sand.

Reproduction

In the wild, Clypeaster humilis reproduces by releasing eggs and sperm into the water column in a process known as broadcast spawning. In the aquarium, however, reproduction is rare. If successful, the larvae will settle and metamorphose into tiny sand dollars.

Habitat

Sand Dollars are typically found in shallow, sandy or muddy sea beds in warm temperate and tropical waters. They are adept at burrowing and often partially embed themselves in the substrate to feed and avoid predators. Clypeaster humilis can be found at various depths, often ranging from the intertidal zone to several meters below the surface.