Despite how you might find them in pet stores, fiddler crabs won't be happy or healthy in a completely underwater home. Fiddlers need to be able to climb out of the water and get some fresh air.

Can fiddler crabs drown?

Although they have gills, Fiddler crabs can drown if there is too much water. They retreat to their 12″ burrows in the sand at high tide and seal the burrow with mud or sand.

Do fiddler crabs breathe air?

All crabs have gills, but crabs that live on land, like the fiddlers, breathe air instead of water. Their gills must stay wet to work, so they must stay near water at all times.