Hermit crabs are omnivorous and opportunistic scavengers, sustaining themselves on what they can find. In captivity, you can tailor the diet of hermit crabs to ensure all their nutritional needs are met.
For a strong exoskeleton, hermit crabs need a diet rich in protein and calcium.
Meat and fish, eggs, nuts, and leafy greens are safe for hermit crabs to eat. Fresh fruit is popular as hermit crabs have a sweet tooth. Also, hermit crabs like having wood, moss, and algae in their tank.
Don’t make the mistake of assuming that, because hermit crabs are scavengers, they can eat anything.
Are Hermit Crabs Carnivores or Herbivores?
Hermit crabs are omnivores, which means they’ll eat a plant or meat-based diet.
As natural scavengers, wild hermit crabs can’t be overly fussy about food, so they’ll eat an apple core or the carcass of a dead conspecific. The most important consideration is the make-up of their food.
Hermit crabs need protein and calcium above all else, which keeps them strong and healthy. Also, appropriate levels of carbohydrates are needed for energy.
One positive of scavenging is that hermit crabs are never short of options. According to the Journal of Experimental Marine Biology and Ecology, hermit crabs seldom eat the same food twice in 24 hours.
So, hermit crabs fully embrace their omnivorous nature. No hermit crab will ever gorge exclusively on meat or plant-based matter because dietary diversity is crucial to keeping hermit crabs interested in food.
How Do Hermit Crabs Eat?
To eat, hermit crabs rely upon their pincers, known as the chelipeds. Healthy, intact hermit crabs have two chelipeds at the front of their body; these are considered the foremost pair of legs.
In most cases, the right cheliped is larger and dominant. Hermit crabs use this pincer to pick up food and bring it toward their mouth; the smaller cheliped is used to guide food into the mouth.
Hermit crabs don’t have teeth but small mouthparts, which are used to grind food until it’s small enough to swallow. So, hermit crabs flourish when food is provided in small, bite-sized chunks.
Also, this will reduce food waste. As hermit crabs are small, they don’t eat significant amounts. Most hermit crabs will be content to nibble until they’re no longer hungry before moving on with their day. If a hermit crab is gorging on food, it’s likely preparing to molt.
If hermit crabs have shed their chelipeds, they’ll need to be hand-fed. For small snacks, this can be done from your palm, but not all hermit crabs tolerate handling well.
In these instances, feed your hermit crabs by offering food on a plastic spoon.
How Often Do Hermit Crabs Eat?
Hermit crabs can survive for several days without food, sometimes as long as two weeks.
If a hermit crab knows that it’ll be without access to food for a prolonged period, it’ll eat to excess. The more fat a hermit crab consumes, the longer it can safely fast.
Most hermit crabs will avoid this eventuality. Even if a hermit crab is scheduled to molt and can’t scavenge for weeks, it’ll eat its shed exoskeleton. This provides all necessary calories and nutrients until it resurfaces to scavenge again.
Just because hermit crabs can live without food doesn’t mean they should. Like any animal, hunger impacts the behavior of hermit crabs. As per the Bulletin of Marine Science, ravenous hermit crabs grow aggressive and cantankerous, especially when food is scarce.
Wild hermit crabs usually eat once a day, emerging once the sun goes down to look for nourishment. This should be replicated in captivity, so provide food before dusk because this is when hermit crabs will wake up, likely feeling hungry.
What Do Wild Hermit Crabs Eat?
This depends on whether the hermit crabs dwell primarily on land or in the ocean. Many wild species of hermit crabs are strictly aquatic, so they’ll remain on the seabed floor, rarely surfacing.
Aquatic hermit crabs sustain themselves on:
- Coral reefs
- Mollusks and small snails
- Dead animals
Land hermit crabs won’t enter the water unless necessary. Many species of fish and other marine lifeforms are natural predators of hermit crabs, and a land-based crab can’t defend itself from such foes.
This means that terrestrial hermit crabs scavenge after sundown, seeking nourishment from:
- Moss and leaves
- Food left by human visitors to the beach
- Fecal matter
- Cadavers of dead animals
If you bring hermit crabs into your home, initially attempt to replicate a wild diet because this will help the hermit crabs adjust. Hermit crabs experience post-purchase syndrome, which is a period of intense stress caused by the transition from wild to captive life.
What Do Hermit Crabs Eat in Captivity?
A more pertinent question should be, “what do hermit crabs like to eat?” By spoiling your hermit crabs with safe yet delicious foods, life in captivity will be more agreeable.
Many hermit crabs struggle with adaptation to life as a pet. Review this safe hermit crab foods list and provide a tasty, varied diet because this will improve their quality of life.
Contents of an Aquarium
As mentioned, wild hermit crabs sustain themselves on anything they find in their environment, and this survival instinct is retained in captivity. So, don’t be surprised or alarmed if your hermit crabs eat wood, moss, algae, or corals in a tank.
Marine hermit crabs act as janitors in a fish tank, preventing unsightly algae from overflowing. Land hermit crabs will also nibble on organic matter in their tank.
Ensure that any wood you use in a habitat is safe for hermit crabs to consume, and regularly spot clean an aquarium so that they don’t consume mold growths.
A hermit crab tank will likely become a mini ecosystem.
Many different insects will make a home within the aquarium. While these will need to be purged by cleaning every couple of months, they serve their purpose in the interim.
Hermit crabs aren’t natural hunters, but they’ll eat insects in their habitat. However, captive hermit crabs should not sustain themselves on insects alone, but they are an appealing side dish.
If you keep aquatic hermit crabs, there’s every chance they’ll share a tank with fish. If so, you’ll find that hermit crabs help themselves to leftover fish flakes.
Check the ingredients of your chosen fish food to ensure they don’t contain any chemicals. If safe, hermit crabs will love these floating treats. Quality fish flakes can be a treat for terrestrial hermit crabs.
You can grind cuttlebone into powder and add it to food or leave a free-standing slab of cuttlebone in the substrate. Hermit crabs will work their way through the latter at their leisure.
Cuttlebone is the cuttlefish’s skeleton, a cephalopod resembling a squid. This skeleton is packed with calcium, making it ideal for hermit crabs. Unlike most foods, you can also provide cuttlebone constantly, as hermit crabs are unlikely to tire of this ingredient.
Fresh Fruit and Vegetables
Fruit and vegetables are essential to the diet of hermit crabs. Whenever you head to the supermarket, get fresh, organic produce. The sweeter the food the better, as far as hermit crabs are concerned. Strawberries, grapes, bananas, and peppers are all firm favorites.
You can offer leafy greens, too. These are usually rich in calcium, so they’re a good addition to the diet. They lack any distinct scent, which means that hermit crabs may initially reject these foods.
Meat and Fish
Hermit crabs are omnivorous, so they aren’t averse to eating meat.
As per Marine Ecology Progress Series, hermit crabs can resort to cannibalism. It’s common for hermit crabs to consume dead comrades in the wild and captivity.
This doesn’t mean that hermit crabs should be served raw meat or fish. Always get the highest-quality meats, and cook the meat thoroughly, allowing it to cool before serving.
Hermit crabs have small bodies and appetites, so they won’t need an entire steak. Cut any meat into small, bite-sized chunks and serve it sparingly.
Hermit crabs often love oatmeal, especially if it’s sweetened with honey.
Go easy on the milk if offering oatmeal to hermit crabs because lactose is often difficult for them to digest. If you use oat-based milk for moisture, so much the better.
In addition to oatmeal, offer oatcakes to nibble on. These can be broken apart and eaten at will. Also, they don’t rot, preventing the build-up of bacteria in the tank.
Eggs are an abundant source of protein (amino acids). Scrambled eggs, in particular, are a favorite food.
Be mindful of how you cook eggs. Don’t add anything that would appeal to the human palate, such as salt or pepper; eggs are more than enough to satisfy hermit crabs.
Also, hermit crabs will benefit from consuming eggshells. Grind these shells into small pieces and mix them with scrambled eggs for additional calcium.
Nuts, Seeds, And Grains
These foods are beneficial to hermit crabs due to their high protein content. Hermit crabs also don’t need to worry about the fat in nuts, which can benefit them, especially ahead of a molt.
Crush the nuts into a fine powder or chop them into small pieces and serve in a bowl. Remember that hermit crabs do not have teeth, so any serving that’s too large is a choking hazard.
The following are among the favorite nuts and seeds enjoyed by hermit crabs:
- Brazil nuts
- Pumpkin seeds
- Sunflower seeds
Avoid seeds from fruits as they often contain arsenic.
Peanut Butter and Jam
Peanut butter and fruity jam are good treats for hermit crabs.
While hermit crabs love these foods, they should be hand-fed from the tip of the finger. If you leave a jar or spoonful of peanut butter in an enclosure, hermit crabs will amass, but they’re messy eaters.
Hermit Crabs Unsafe Food List
You may be forgiven for thinking that hermit crabs have iron constitutions, capable of eating anything. After all, if they survive in the wild by scavenging, they must occasionally find undesirable foods.
As per The Biological Bulletin, hermit crabs avoid foods that have made them unwell. The journal describes this as “serious physiological upset,” typically associated with emotional responses.
Feeding inappropriate food may damage the trust hermit crabs have in you. To this end, you must understand which foods are unsafe and unsuitable for hermit crabs.
Hermit Crab Pellets
If you’re new to caring for hermit crabs, pellets like an easy dietary option.
Theoretically, hermit crab pellets are palatable, appropriately sized sources of everything a hermit crab needs. Think of this foodstuff as the equivalent of small animal muesli. In reality, many hermit crab enthusiasts consider pellets toxic.
It’s claimed that pellets contain harmful preservatives and heavy metals, such as copper. A common claim is that pellets are made from general food waste bound together.
Learn what’s in pellets and how they’re made. Even then, there’s no guarantee that hermit crabs will eat the pellets because most find them dull and devoid of flavor.
Moldy or Aged Foodstuffs
As hermit crabs are scavengers, they’ll likely eat moldy food in the wild. However, this doesn’t mean that spoiled food is good for them. If you have spoiled food, throw it in the garbage.
A slightly wrinkled grape is OK because hermit crabs won’t be concerned by the texture. If fruit or meat is rotten, it’s unsafe for hermit crabs to consume.
Saline water is an essential addition to any hermit crab enclosure. Hermit crabs rely upon saltwater to activate their senses, most notably smell. As per Proceedings of the Royal Society, saltwater vapors aid hermit crabs in detecting food aromas.
The salt applied to dechlorinated water can’t be table salt, though. This kitchen cupboard staple contains large quantities of iodine.
Iodine is an essential chemical element in human consumption, promoting a healthy thyroid gland. Hermit crabs also need small quantities of iodine to aid a healthy molt. It’s easy for hermit crabs to get too much iodine, which is highly toxic.
When mixing salt into water, use marine salt. If you run out, don’t use table salt as a substitute.
Pesticides and Herbicides
We recommended getting organic to avoid harmful chemicals. It’s not just fresh fruit and vegetables that merits this investigation because some meats are treated with ethoxyquin.
Any artificial chemical is harmful to hermit crabs, so you must be vigilant about keeping such materials away from hermit crabs.
Be careful when using potting soil as an alternative substrate or gathering wood from nature.
Onions and Garlic
Hermit crabs can’t develop anemia, but this doesn’t make onions or garlic safe.
Onion and garlic are fatal to insects. While hermit crabs are crustaceans, not insects, they’re invertebrates, which means they share many qualities with their six-legged brethren.
This issue is complicated by commercial hermit crab foods containing traces of onion due to the strong scent of the vegetable.
It’s claimed that citrus fruits, such as oranges and lemons, are toxic to hermit crabs. However, this is untrue. The belief stems from citrus trees because the bark contains natural anti-pesticides.
Most hermit crabs will show no interest in citrus fruits because the scent alone will likely deter them from approaching. Even the smallest slice of lemon or orange may make an entire meal unpalatable.
Hermit crabs aren’t fussy eaters, but this doesn’t mean you can offer them anything. You must meet hermit crabs’ nutritional and lifestyle needs and avoid anything that would harm them.