Are sand dollars reef safe?




Do you love collecting sand dollars but are unsure if they are reef safe? If so, you’ve come to the right place! In this blog post, we’ll discuss the pros and cons of collecting sand dollars and answer the big question – are sand dollars safe for your reef tank?

Let’s dive in!

Reef Compatibility of Sand Dollars

Sand dollars are generally considered to be reef-safe. They are not known for eating coral or damaging the reef in any way.

However, they may change the pH and affect the reef in other ways, so it is important to make sure that your tank is well-maintained and has the right water parameters before adding a sand dollar.

Additionally, due to their maximum size of 8.5 cm, they can eventually shade corals below them, so it is important to consider the placement of the sand dollar when deciding whether or not to add one to your reef aquarium.

Sand dollars will not eat coral reef

Sand dollars are not reef-safe, as they are known to attack coral reefs and other invertebrates in the wild. As such, it is not recommended to keep them in home tanks. Sand dollars feed throughout the day, so they do not need to be hand-fed; they can naturally feed themselves from fish waste and tiny invertebrates.

Additionally, sand dollars need a very deep sand bed and a particular type of substrate particle size. Sand dollars are known to change pH levels in the water, which can affect the reef. While their maximum size is relatively small compared to other marine life, sand dollars can still cause damage if left unchecked. Therefore, it is best to avoid keeping sand dollars in reef aquariums.

Natural Habitat of Sand Dollars

The common sand dollar, Echinarachnius parma, can be found in the Northern Hemisphere from the intertidal zone to the depths of the ocean. In its sandy seafloor habitat, a sand dollar uses its spines, aided by tiny hairs (cilia), to ferry food particles along its body to its mouth. Most sand dollars live in seawater (saline environments), although some species do occur in estuarine habitats which combine of river and lake water. As sand dollars are not natural predators to coral reefs and most of them feed on small particles in the ocean, it is safe to say that they will not consume coral or other reef creatures. However, they may affect the reef indirectly as they can change pH levels and cause sedimentation.

They may change pH and affect the reef

Although sand dollars do not eat coral reef, they may have an effect on the pH of the water. As mentioned earlier, coral reef aquaria can succeed in a wide range of pH values, but the ideal range is around 8.2. Sand dollars may cause a lowering of pH levels which can be detrimental to coral health. Therefore, it is important to monitor pH levels if you have sand dollars in your aquarium. Additionally, it is important to ensure that your aquarium has the right parameters for these creatures to thrive and that their maximum size does not exceed 6 inches.

Maximum Size for Sand Dollars

Sand dollars have a maximum size of 8.5 cm, which is very small compared to other animals in a reef aquarium. As they reach adulthood, they can grow to a width of up to 120 mm, making them ideal for small reef tanks. It is important to note that they require a large sand bed in order to thrive, as they are benthic sand eaters. Spot injection of cyclopeeze every now and then may be required to ensure their health and wellbeing. While they are small in size, sand dollars can still have an effect on the pH and water quality of the tank if their numbers become too high.


In conclusion, sand dollars are generally reef safe and can make a good addition to a reef tank. They will not eat coral, however, they may change the pH levels of the tank and affect the reef. It is important to remember that sand dollars reach a maximum size which should be taken into account when deciding where to place them in the tank. With proper care and handling, sand dollars can make an interesting and unique addition to any aquarium.

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