What Do Hermit Crabs Eat? Complete Safe & Toxic Food List

Hermit crabs are omnivorous scavengers. In the wild, they eat fallen fruit, decaying wood, leaf litter, carrion, seaweed, and whatever else washes up on the shore. They are not picky — but they are surprisingly sensitive to chemicals, pesticides, and certain compounds that are harmless to mammals but toxic to invertebrates. Feeding your hermit crabs well is about variety, freshness, and avoiding a short list of dangerous items.

The Golden Rule: Variety

No single food is "the best" hermit crab food. What matters is rotation. In any given week, try to offer items from each of the following categories: protein, fruit, vegetable, calcium source, and a wild card (leaf litter, bark, seaweed). Rotate daily. Hermit crabs get bored — or more precisely, they instinctively seek nutritional diversity. A crab that ignores mango on Monday may devour it on Thursday if it's been eating shrimp all week.

Safe Fruits

Hermit crabs love most tropical and temperate fruits. Great options include:

• Coconut (fresh or dried, unsweetened — a perennial favorite)
• Mango (ripe, soft pieces)
• Banana (including the peel if organic)
• Apple (remove seeds — they contain trace cyanide)
• Papaya, grapes, blueberries, strawberries, watermelon

Always wash fruit thoroughly or buy organic. Pesticide residue is a serious concern for invertebrates. Even small amounts of common insecticides can be lethal to hermit crabs.

Safe Vegetables

Offer a mix of raw and lightly blanched vegetables:

• Spinach and kale (excellent calcium and mineral source)
• Sweet potato (cooked or raw — high in beta-carotene, which enhances shell color)
• Carrots (raw, grated or small pieces)
• Zucchini, cucumber, broccoli, peas
• Seaweed / nori sheets (unseasoned — loaded with trace minerals)

Avoid iceberg lettuce — it is nutritionally empty. Dark leafy greens are always the better choice.

Protein Sources

Protein is essential, especially before and after molting. Offer 2–3 times per week:

• Dried shrimp, krill, or mealworms (available at pet stores)
• Fresh cooked shrimp, fish, or chicken (unseasoned, no salt or oil)
• Boiled egg (including crushed shell for calcium)
• Bloodworms or brine shrimp (freeze-dried)
• Crickets (dried or freeze-dried)

Never use seasoned, salted, or processed meats. No deli meat, no sausage, no canned tuna in oil.

Calcium Sources

Calcium is critical for exoskeleton hardening after a molt. Always keep a calcium source available:

• Cuttlebone (the #1 choice — place a piece in the tank permanently)
• Crushed oyster shell
• Crushed eggshell (baked at 100 °C / 212 °F for 10 minutes to sterilize)
• Coral sand or aragonite
• Calcium-fortified dried seaweed

Without adequate calcium, molts are more likely to fail — the new exoskeleton comes in too soft and the crab cannot support its own weight.

Leaf Litter and Bark

In the wild, hermit crabs eat a surprising amount of decayed plant material. Add these to the tank as both food and enrichment:

• Oak leaves (dried, pesticide-free)
• Indian almond leaves (catappa) — also have mild antibacterial properties
• Cork bark
• Coconut husk fiber
• Dried moss

These items can stay in the tank for weeks. Crabs graze on them slowly and they contribute to a naturalistic environment.

Toxic and Dangerous Foods

These should never be offered:

• Citrus in excess — small amounts of orange are okay, but large quantities of lemon, lime, or grapefruit irritate the gill tissue and digestive tract
• Onion and garlic — contain thiosulfates that are toxic to many invertebrates
• Anything with pesticides — this is the #1 killer; always wash produce or buy organic
• Commercial hermit crab food from pet stores — most contain ethoxyquin, copper sulfate, and artificial preservatives that are harmful long-term
• Salty, processed, or fried food — table salt (sodium chloride without trace minerals) dehydrates gill tissue
• Dairy products — crabs cannot digest lactose
• Chocolate, coffee, or caffeine — toxic to invertebrates

Feeding Schedule

Offer fresh food every evening (hermit crabs are nocturnal). Remove uneaten fresh food each morning to prevent mold. Dry items like cuttlebone, leaf litter, and dried shrimp can stay in the tank permanently.

Use shallow, non-metallic dishes. Ceramic or coconut shell halves work perfectly. Metal dishes can leach trace amounts of copper or zinc, both of which are toxic to crabs.

Water as Food

Both freshwater and saltwater pools serve double duty — hydration and mineral intake. Crabs drink from both, and they store water in their shells to keep their gills and abdomen moist. Use dechlorinated freshwater and marine salt mix (not table salt) for the saltwater pool. Both pools should be deep enough for the largest crab to submerge but have a ramp so small crabs can climb out.

Final Thoughts

Feeding hermit crabs is one of the most enjoyable parts of keeping them. They have genuine preferences and will clearly show you what they love by devouring it overnight. Rotate through the safe foods list, keep calcium always available, avoid anything treated with pesticides or chemicals, and enjoy watching your crabs feast.