Common name: Sand Dollars

Clypeasteridae, commonly known as sand dollars, are a family of sea urchins characterized by their flattened, burrowing lifestyle. They are found in sandy or muddy substrates in shallow waters. Sand dollars have a fascinating petal-like pattern on their upper surface, which is actually a system of pores that aid in respiration. They feed on detritus, microalgae, and organic material, making them excellent sandbed cleaners in aquariums. Hobbyists appreciate them for their unique shape and behavior, but they require stable water conditions and a sandy substrate to thrive.

1. 
   Common name: Sand Dollar

   Scientific name: Clypeaster humilis
2. 
   Common name: Sand Dollar

   Scientific name: Clypeaster reticulatus
3. Common name: sea biscuit

   Scientific name: Clypeaster rosaceus
4. 
   Common name: sand dollar

   Scientific name: Clypeaster subdepressus