What Do Hermit Crabs Eat? Complete Diet and Feeding Guide

Most hermit crabs do well when the base of the diet is a commercial food made for hermit crabs. PetMD recommends feeding once daily and following the manufacturer’s directions for amount. For small crabs, pellets may need to be crushed.

Fresh vegetables can be offered very often, including spinach, carrots, kale, romaine, bell peppers, and cucumber. These foods add variety and moisture. Fruits can also be offered, but less often because they are sweeter. Good options include mango, coconut, papaya, strawberries, apples, and bananas.

A practical routine is to offer the staple food nightly, add a small vegetable portion most days, and rotate fruit and protein treats through the week. That approach helps reduce boredom without turning treats into the main diet.

Yes. Hermit crabs are scavenging omnivores, so they benefit from some animal-based or marine-based protein in addition to plant foods. PetMD lists brine shrimp and fish flakes as occasional treat options, and some crabs also accept tiny amounts of crab-safe dried seafood.

Calcium is especially important because the exoskeleton depends on it. PetMD advises offering a calcium supplement or a natural calcium source such as crushed cuttlebone. This becomes even more important around molting, when the body is rebuilding the shell-like outer covering.

If your crab seems to ignore calcium sources, do not force a supplement plan on your own. Your vet can help you review the full diet and habitat, since poor calcium intake may overlap with stress, dehydration, or other husbandry issues.

Hermit crabs should generally be fed once a day, with feeding done at night. PetMD specifically recommends nighttime feeding because hermit crabs are nocturnal. Uneaten food should be removed the following morning to limit mold, bacteria, and pest problems.

Hermit crabs eat slowly and take tiny bites, so small portions are usually enough. It is better to offer modest amounts consistently than to overfill the dish. If food is routinely untouched, review temperature, humidity, water access, and recent molting behavior before assuming the problem is the food itself.

Safe treat categories include small amounts of fruit, nuts, seaweed, brine shrimp, and fish flakes. PetMD recommends fruits no more than one to three times a week and nuts, seaweed, brine shrimp, and fish flakes no more than two to three days a week. Nuts should stay limited because they are high in fat.

When offering produce, wash it in purified, distilled, or bottled water first. Keep portions small, avoid seasoned or processed foods, and remove leftovers promptly. Variety is helpful, but balance matters more than novelty.

One common mistake is relying too heavily on fruit or fatty treats. Another is leaving food in the enclosure long enough to spoil. PetMD also advises using non-metal, non-porous bowls such as hard plastic or ceramic, because hermit crabs are sensitive to metals and porous dishes are harder to disinfect.

Another issue is offering a cafeteria-style diet with too many random choices and no real staple. Merck Veterinary Manual notes that free-choice cafeteria feeding is discouraged in captive animals because they often do not select a balanced diet on their own. For hermit crabs, that means a structured feeding plan is usually safer than constant access to a pile of mixed treats.

If your crab has repeated appetite changes, weight loss, or trouble after molting, your vet can help assess whether the issue is diet, habitat setup, or an underlying medical problem.

Hermit crabs need constant access to both fresh water and salt water. PetMD recommends shallow dishes that allow the crab to enter and exit easily. Water access is part of nutrition and hydration, not a separate extra.

Because dehydration and poor husbandry can affect appetite, a crab that is not eating well may need a full review of feeding, humidity, substrate, and water setup. Your vet can help you decide what changes are most appropriate for your individual pet.