How to Feed a Sand Dollar in a Saltwater Tank

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Answered by: Kim, An Expert in the Fish and Invertebrates Category
Everyone has seen beautiful sand dollars in saltwater tanks and when starting a new aquarium you may have some questions. You may be wondering about feeding a sand dollar in a saltwater tank and asking yourself, "What do sand dollars eat and how often is a sand dollar fed?"

A sand dollar is a peaceful creature that can thrive in a saltwater tank. Sand dollars are a type of sea urchin and their scientific name is of the Clypeasteroida species. Unbelievably, the sand dollar is very easy to feed because there is not much that you need to do, just a few things to keep in mind so that your sand dollar can live a long and healthy life.

What Do Sand Dollars Eat?

Wondering about how to feed a sand dollar and especially, how to feed a sand dollar in a saltwater tank? The sand dollars eat by a method of suspension feeding. What this means is that the organic material that includes waste and algae that floats in the water currents is naturally suspended in the aquarium and allows the sand dollar to grab onto these particles through a variety of methods.

The sand dollar uses its tube feet, spines, mucous producing glands and tiny pincer organs with moving jaws called pedicellariae, to eat the particle matter in the aquarium's water. Their spines are coated in cilia that helps as well. When the organic material float onto these areas, the mucous traps the food and the mucous streams that are near the mouth area leads the food to the sand dollar.

Sometimes there are larger food particles and even living food that is eaten by the sand dollar. This is achieved by the spines that enclose the prey and pass it along to the feeding area with the jaws. At times, sand is eaten along with food and it is believed that this is a deliberate act by young sand dollars to help them stabilize in the substrate by allowing it to weigh them down.

How Often Does a Sand Dollar Need to be Fed?

Since the sand dollar eats naturally and doesn't theoretically need to be hand fed, there isn't a set time that they need to be fed by an aquarium owner. As long as the aquarium that they are housed in has a sufficient amount of organic matter in it, the sand dollar can thrive on that alone. This is achieved naturally through waste from fish and invertebrates and the natural algae that grows in any saltwater fish tank. With that being said, it is not a good idea to try to keep a sand dollar in a newly established tank because the food that they need to eat will not be available yet and they may not flourish as well as they would in a tank that has been set up for a longer period of time.


Sand dollars are exquisite sand creatures that don't require a lot of knowledge or special care in order to keep them fed. What do sand dollars eat? If they are in a well established tank that has the necessary algae, plankton and detritus that they need, they will eat on their own and flourish.

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