What Do Hermit Crabs Eat?

Before getting a pet hermit crab, you might ask yourself, “What do hermit crabs eat?” Thankfully, their diet isn’t all that complicated. In the wild, land hermit crabs are omnivores, meaning they eat both plant and animal matter. In captivity, their diet should be based on a balanced commercial food supplemented with a variety of fresh foods and treats.

Keep reading to learn what foods to feed your hermit crab and which ones to avoid.

Commercial Diets

There are a few good commercial diets available (though it may be difficult to find them at smaller pet shops, depending on where you live). Fortunately, there are mail order sources readily available.

Florida Marine Research (FMR) is a good source of time-tested commercial food as well as treats. Zoo Med is another reputable manufacturer that makes a pelleted diet and treats to tempt even the pickiest eaters.

Pelleted foods can be fed once a day, and should be crushed, especially for smaller crabs. They can also be moistened if desired. Uneaten food, including pelleted/commercial foods, should be removed daily.

Fresh Foods and Treats

While the commercial diets are convenient and most are quite well balanced, they should be supplemented with fresh foods. Hermit crabs seem particularly fond of having a varied diet. A wide variety of foods from the list below should be offered on a rotating basis (a few one day, then a handful of others the next, and so on).

Fresh foods and treats you can try include:

• Mango
• Papaya
• Coconut (fresh or dried)

• Apples
• Applesauce
• Bananas
• Grapes
• Pineapple
• Strawberries
• Melons
• Carrots
• Spinach
• Watercress
• Leafy green lettuces (not iceberg/head lettuce)
• Broccoli
• Grass
• Leaves and strips of bark from deciduous trees (no conifers)
• Nuts (unsalted nuts)
• Peanut butter (occasionally)
• Raisins
• Seaweed (found in some health food and grocery stores for wrapping sushi)

• Crackers (no or low salt)
• Unsweetened cereals
• Plain rice cakes
• Popcorn (plain, air popped, can be given occasionally)
• Cooked eggs, meats and seafood (in moderation)
• Freeze dried shrimp and plankton (found in the fish food section at the pet store)
• Brine shrimp
• Fish food flakes

This list is not exhaustive, but almost any fruit (fresh or dried) can be offered, although some experts recommend avoiding highly acidic or citrus foods (e.g., oranges, tomatoes, lemons, and limes).

What You Shouldn't Feed a Hermit Crab

Avoid feeding hermit crabs starchy vegetables, such as potatoes, and stay away from iceberg lettuce, as it is of very low nutritional value. Crabs may really like salty, fatty, or sugary snacks, such as pretzels, chips, and sweetened cereal, but these should be avoided. Avoid feeding dairy products as well.

Calcium

Hermit crabs need calcium to support the health of their exoskeleton, and this is especially true during molting. Ways to provide ample calcium to your crabs include the following:

• Cuttlebone: Available in pet stores (check the bird section) and can be given whole or shredded and added to food
• Calcium vitamin supplements: Available for reptiles, these can also be added to hermit crab food
• Crushed oyster shell: Also from the bird section, this is an excellent source of calcium
• Coral sand: Use the fine sand as tank substrate or a supplement
• Crushed egg shells: Boil, dry, and crush some egg shells for an easy source of calcium

Water

All species of hermit crabs should have access to both fresh water and salt water. Fresh water is needed for drinking, and most hermit crabs will also drink salt water (some also like to bathe in the salt water, so providing a dish of salt water big enough for the crab to get into is a good idea).

All tap water must be treated with a dechlorinator (drops available at pet stores) to remove harmful chlorine and chloramines.

For preparing the salt water, use a product such as Instant Ocean which is designed to imitate natural salt water. The salt designed for fresh water fish (for treating illness, etc.) is missing some components of natural salt water. Never use table salt. The desired salinity of the water is somewhat debated among owners. For most crabs, mixing the proportion of salt and water indicated to produce the concentration for a saltwater (marine) fish tank is probably fine, and the crabs will adjust their intake of salt water and fresh water to regulate their salt needs.

Food and Water Dishes

For food dishes, you will want something shallow, sturdy, and easy to clean. Flattened heavy plastic dishes made to look like rocks can be found in the reptile section, or you can use shallow ceramic dishes made for small animals. Some people also use natural seashells (the flatter half shells) for feeding.

Since all species of hermit crabs should have access to both fresh and salt water, you will need two water dishes. They should be big and deep enough to let the crabs get into them if they wish to soak (especially the salt water dish), but easy to get out of and not so deep that drowning is a risk (strawberry hermit crabs should be given a salt pool deep enough to fully submerge themselves, but for most species it does not need to be that deep).

With deeper dishes, smooth river stones or pieces of coral can be used as ramps or steps for the crabs to get out of the water. You should also place natural sea sponges in the water dishes. Some crabs will press on these sponges to get water to drink, and they help regulate the humidity in the enclosure.