Avocado!

Avocado is a favorite among hermit crabs. It is native to the Caribbean, Mexico, South America and Central America. PPs and Es live in and around those areas, so it's likely part of their diet in the wild.

The avocado is colloquially known as the Alligator Pear, reflecting its shape and the leather-like appearance of its skin. "Avocado" is derived from the Aztec word "ahuacatl".

Alligator Pears have Zeaxanthin which helps by enhancing color of the exoskeleton, it also aids in body functions.

So definitely, try it! Just avoid the actual plant, the skin and seed too. Only the meat is for crab consumption.