As for food, they can eat a variety of fruits and meats cooked or raw, but certain food are not good for them. i found this list of safe and unsafe food from a hermit crab forum called hermit crab association.
a quote from HCA (do note that this list is not mine and all credit goes to the website)
Safe food for hermits :
Acorns (crush and soak overnight in salt water then drain before serving)
Alfalfa
Almonds, crushed
Amaranth (Ancient grain)
Anchovy oil
Apple and natural, unsweetened apple sauce
Apricot
Arame
Artichokes
Asparagus
Avocado
Bamboo (live plants make wonderful tank toys and grazing)
Banana
Barley
Beans, yellow wax
Bell peppers (red, yellow, orange, green or purple)
Bee pollen
Beets
Bilberries/Huckleberries
Blackberry leaves
Blackberry
Blackstrap molasses (unsulfured) - amazingly high in nutrients such as calcium and potassium; 1-2 times monthly
Bladderwrack
Bloodworms (alive or dead)
Blueberries
Borage blossoms (Borago officinalis)
Broccoli and leaves
Brown rice
Brussels sprouts
Cabbage (all varieties)
Calcium carbonate powder, plain
Calendula flowers (Calendula officinalis)-Also known as "pot marigolds"
Camellia (Camellia japonica)
Canteloupe
Carnation flowers (Dianthus caryophyllus)
Carrots
Carrot tops
Cauliflower and leaves
Celery leaves
Cereal; Brown rice, soy, wheat or 7 grain, muesli
Chamomile flowers
Chard
Cheese (be sure to get all natural varieties, serve as occasional treat)
Cherimoya
Cherry
Chestnuts
Chicken bones
Chicken, cooked and unseasoned (smash the bone for marrow access)
Chickweed
Cholla wood
Cilantro
Citrus (all fruits)
Clams
Clover blossoms and leaves
Coconut and coconut oil
Cod liver oil
Collards
Cork bark
Corn (on the cob, too)
Cornmeal
Cranberries (dehydrated)
Crickets
Crustaceans (any and all crustacea including crayfish, lobster, shrimp and other crabs)
Cucumber
Currants
Cuttlefish bone, powdered
Dairy products (milk, cheese, live-culture yogurt) **
Daisies (Bellis perennis)
Dandelion flowers, leaves and roots (Taraxacum officinale)
Day lilies (Hemerocallis)
Egg, scrambled or soft boiled
Eggplant
Eggshells
Elderberry flowers (Sambucus canadensis)
Extra-virgin olive oil
Fig (ripe fruit only)
Fish flakes w/out chemical preservatives
Fish Oil
Flax seeds/Linseeds (crushed)
Flax seed oil (small amounts infrequently)
Frozen fish food (esp. algae, krill and brine shrimp)
Garbanzos
Gladiolus (Gladiolus spp.)
Gooseberry (ripe or overripe)
Grape Leaf
Grapes
Grapevine (vines and root)
Green and red leaf lettuce (not iceburg; dark green)
Green Beans
Hazel leaves
Hempseed Meal
Hibiscus flowers (Hibiscus rosa-sinensis)
Hikari products: brine shrimp, krill, crab cuisine, sea plankton (no preservatives)
Hollyhock flowers
Honey (organic, or at least locally produced, for anti-microbials)
Honeybush
Honeydew Melon
Honeysuckle flowers (Japanese Lonicera japonica)
Impatiens (Impatiens wallerana)
Irish Moss
Japanese red maple leaves, dried (Acer palmatum)
Jasmine flowers (Jasmine officinale)
Johnny-Jump-Up flowers--(Viola tricolor)
Kamut
Kelp
Kiwi
Lentils
Lilac (Syringa vulgaris)
Lima Beans
Lobster with crushed exoskeleton
Locusts (dead)
Lychee fruit (fresh; no kernel)
Macadamia nuts
Madrona wood
Mango
Mangrove (small live trees can be obtained on eBay, use in water basin)
Maple leaves
Maple syrup
Marion Berries
Milk thistle flowers (Silybum marianum)
Mint (but not peppermint!)
Most organic baby foods
Muscadine (grapes)
Mushrooms
Mussels
Nasturtium flowers (Tropaeolum majus)
Nettle (wilted)
Nettle, stinging (pour boiling water over leaves first)
Oak Leaves and bark
Octopus
Okra
Olive and olive oil (extra virgin)
Oranges
Oysters
Pansy flowers and leaves (Viola X Wittrockiana)
Papaya
Parsley
Parsnip
Passionflowers (Passifloraceae - passion flower family)
Passionfruit
Peaches
Peanut butter (avoid sugar, corn syrup and hydrogenated oils)
Peanuts
Pears
Peas
Pecans
Pecan bark
Persimmon
Petunia blossoms
Pineapple
Pistachio nuts
Plum
Pomegranate
Popcorn (unseasoned, unflavored, unbuttered)
Potato (no green parts, including eyes)
Psyllium & husks
Pumpkin
Purslane (Portulaca oleracea)
Quinoa (New World grain)
Raisins (no sulphur dioxide)
Raspberry
Red raspberry leaves (highest bioavailable calcium source + vit. C and trace minerals)
Rolled Oats
Rooibus (or rooibos)
Roquette (Eruca vesicaria)
Rose petals (Rosa spp)
Rose hips
Royal Jelly
Russian Olive leaves (Elaeagnus angustifolia)
Sage blossoms (Salvia officinalis)
Salmon
Sand dollars
Sardines
Scallops
Sea biscuits
Sea fan (red or black)
Sea grasses
Sea salt
Sea Sponges
Semolina
Sesame seeds (crushed)
Sesame oil (in tiny amounts as appetite stimulant)
Shrimp and exoskeletons
Snails (use human food grade only; not wild snails)
Sorrel (Rumex acetosa)
Soy and soy products (human grade; miso, tofu, etc.)
Spelt
Spinach
Spirulina (complete protein and chlorophyll source; highest in beta carotene)
Sprouts (flax, wheat, bean, alfalfa, etc.)
Squid
Squash (and squash blossom)
Star fruit (carambola)
Strawberry and tops
Sugar cane
Sunflower Seeds (crushed), flowers and leaves (Helianthus)
Swamp cypress wood (false cypress, taxodium sp.)
Sweet potato
Sycamore leaf
Tahini (no garlic variety)
Tamarillo
Tangerine
Timothy hay
Tomato
Tree Fern
Triticale
Tulip flowers (Tulipa spp.)
Tuna
Turnip greens
Viola flowers
Violet flowers (Viola odorata)
Walnuts
Wasa All-Natural Crispbread (Oat flavor)
Watercress
Watermelon
Wheat grass
Wheat
Wheat germ
Whitefish
Whole Wheat Couscous
Wild rice
Zucchini (and zucchini flowers)*
*This food list is mainly adapted from Summer Michealson and Stacey Arenella's book,
The All-Natural Hermit Crab Sourcebook, and expanded on by Julia Crab and others
** After extensive tests in several EH member tanks, it has been discovered that dairy items are not lethal to crabs. In fact, most crabs really enjoy cheddar cheese, live-culture yogurt, and the occasional drink of milk. While extended long-term testing is still underway, there has been 8 months of trials with no harm to the test crabs. For now, dairy is acceptable, once every 30 to 60 days as a treat. It should not be relied upon as a food base.
Unsafe food for hermits :
While it is true that crabs are scavengers with a wide repertoire of foods they can eat, there
are many plants and foods that just should not be fed to a crab. The foods on this list are to
be avoided. Some are toxic, some are insect repellents or used as insecticides, and some the crabs
just won't go near, such as lemon -- lemon won't hurt them, but they certainly won't eat it.
This list, like the Edible List, will be updated regularly, so be sure to check back often.
Aconite (Monk's Hood)
African violet leaves
African daisy (Osteospermum)
Alder bark
Aloe vera (interferes with potassium absorption)
Amaryllis
American Hellebore
Anemone/Windflower
Aniseed
Avocado leaves
Azalea/Rhododendron
Bay leaves (natural insect repellent)
Bindweed
Bird of Paradise Flowers
Bluebonnet
Bottlebrush flowers
Bougainvillea
Boxwood
Buckthorn
Buttercup
Carnation leaves
Castor Bean
Catnip
Cherimoya Seeds
Chocolate/cocoa
Chrysanthemum
Cinnamon
Citrus (leaves and branches to be avoided; part of the evergreen family. The fruit is fine)
Columbine
Compost (unless 100% organic)
Crocus
Crown of Thorns
Cube Plant
Custard Apple (young fruit)
Cyclamen
Delphinium
Derris
Dieffenbachia
Dill
Dittany
Eucalyptus
European pennyroyal
Evergreen (pine, cedar, juniper, etc.)
Feverfew
Fleabane
Garlic
Geranium
Golden Pothos
Green hellebore
Hemlock
Holly Berries
Horsetail
Ivy (of any kind)
Juniper Berries
Kalanchoe
Larkspur seed
Laurel
Lavender
Lemon Balm (Sweet Melissa)
Lemon Grass
Lucky Bamboo (Dracaena sanderiana)
Mayweed
Mistletoe
Morning Glory
Mulberry leaves
Oleander
Onion
Oxeye daisy
Papaya seed
Parsley Seed (fruit)
Peace Lily
Pencil Tree Cactus
Peppermint
Philodendron
Pine or cedar wood or needles
Prickly juniper
Pride of China fruit
Prunus species trees (apricot, bitter almond, cherry, cherry laurel,
nectarine, peach, plum) Fleshy fruits are edible, everything else
contains a cyanide-like compound and is fatally toxic, including
seeds, wood, leaves, bark and flowers.
Red Emerald
Rosemary
Sago Palm
Sanseveria
Schefflera
Stargazer Lily (Lilium x Stargazer)
Sweet Flag
Tansy
Tea Tree
Texas Mountain Laurel (Sophora secundiflora)
Thornapple
Thyme
Tobacco
Vanillin
Verbena
Vinca
Wild Angelica fruit
Wormwood
Yew
Yarrow
Taken from :
http://www.hermitcrabassociation.com...p?f=25&t=64004
http://www.hermitcrabassociation.com...p?f=25&t=64005
*mod please remove the link if its not allowed thanks*