Fiddler Crabs require brackish water, as well as regular access to dry land. What they don't need is to be tossed in a fully filled freshwater tank. Before you buy one, be sure to learn about the proper care for your Fiddler Crab.
If you see them being improperly cared for at the pet shop, you can do something about it. This customer at a well known chain pet store was able to bring the issue of Fiddler Crab care forward to a person who was in a position to make a change in a significant way. Here is his story about challenging the care of Fiddler Crabs.
Photo © Shirlie Sharpe