Instructions
Food
Keep a steady supply of food in the hermit crab cage at all times. Hermit crabs don't have to be fed at any certain time or any specific number of times per day. As long as there is food in the cage, they will eat when hungry.
Use hermit crab food as a staple. Foods that are sold as hermit crab foods are fortified with vitamins that the animals need. There are also a number of hermit crab treats on the market. They don't have the same nutritional content as the staple foods, but they provide a nice change of pace for a hermit crab. Supplement the packaged foods with small scraps from your own meals. A large crumb of bread or a small piece of fish makes a nice snack for a hermit crab.
Clean out any food that becomes wet. Hermit crabs tend to trample their food and even drag it through water. They may also get their water sponge too close to their food, resulting in a soggy mess. Wet food can mold quickly, and that can create health problems for everyone involved. Anytime the food becomes wet, clear it out, dry off the area and place some new food in the cage. Also clear out any food that becomes contaminated with the crab's droppings.
Get rid of any food that remains in the cage for weeks. If the crabs have several different foods available, one may go uneaten for a long period of time. If so, the crabs simply don't like it. Watch what they are eating and notice any foods that get left behind. Those can be removed and replaced with something that the crabs enjoy.
How to Feed Hermit Crabs
Hermit crabs are scavengers in the wild. By their very nature, they will eat anything edible that they find. This makes hermit crabs one of the easiest pets to feed. There are a number of commercial foods available for pet hermit crabs, but they will eat just about anything else you give them.