Wild hermit crabs drink water daily, so give them the same opportunity in captivity. If hermit crabs don’t drink, they grow dehydrated and their gills dry, leading to breathing difficulties and even suffocation.
Provide access to saline water and freshwater in the hermit crab enclosure at all times.
Saline water can be purchased from an aquatic pet store – don’t make your own with table salt. Never use tap water as fresh water, as chlorine is toxic to hermit crabs.
Keep at least one source of each water option for every 4 hermit crabs in a colony. The hermit crabs will want to submerge themselves in these water dishes to drink and hydrate.
You can also use specialist aquatic sponges to provide hermit crabs with additional water and feed fresh fruits and vegetables with high water content. However, these must be considered supplemental.
Hermit crabs may survive several days without drinking water if their environment is suitably humid, but anything longer than a single day without hydration is life-threatening.
Do Hermit Crabs Dehydrate Without Water?
Alongside an appropriate level of humidity (typically around 80%,) hermit crabs need drinking water to stave off the threat of dehydration. At least two water sources should be resident in a hermit crab enclosure – more if you keep a large colony.
Water is easily accessible for wild hermit crabs. Most hermit crabs live in a beachfront environment, so they can access saltwater from the ocean. When seeking fresh water, hermit crabs rely on rainwater or dew that has gathered on plant life.
If you deprive hermit crabs of drinking water, they’re at risk of dehydration. It’ll also be increasingly difficult for hermit crabs to keep their gills moist.
If left without water for too long, the hermit hermits will suffocate to death.
Hermit crabs bathe in their drinking water, so check it regularly and provide a fresh supply of clean water. This is important if the hermit crab tank has been infested with parasites like mites.
How Long Can Hermit Crabs Survive Without Water?
As per the Italian Journal of Zoology, hermit crabs often fill their shells with water overnight to ensure they always have access to hydration. Refill the water bowls when you wake up.
How long hermit crabs can live without drinking depends on various factors, including:
- Temperature. The hotter your hermit crab habitat, the sooner its skin will dry out.
- Humidity. Higher humidity levels and misting can sustain hermit crabs longer.
- Size. Larger hermit crabs will need more water.
- Age. Young hermit crabs molt more frequently than full adults, so they’ll likely drink more.
Anything longer than 24 hours without water puts hermit crabs at risk. Ask somebody else to refill their water supply if you aren’t around to care for the hermit crabs for longer than a day.
How Much Water Do Hermit Crabs Need?
Larger hermit crabs drink more water than their smaller counterparts. If you have a colony of Purple Pinchers, they’ll drink more than a similarly-number collection of Ecuadorians or Ruggies.
Hermit crabs preparing to molt will appear to drink more, so check for signs that a molt is impending and increase water availability. Hermit crabs will also be thirstier if they eat dry food and exercise a lot.
A golden rule is to have at least two water sources per 3–4 hermit crabs.
As we’ll discuss shortly, one should contain salt water, while the other should host fresh water. Your hermit crabs will sip on this water throughout their waking hours.
Keep these water sources full enough for the largest hermit crab to submerge itself. Include a ramp in your water source so all your pets can easily escape the dish.
Hermit crabs can’t hold their breath indefinitely and drown if left underwater too long.
What Kind of Water Do Hermit Crabs Need?
Hermit crabs need two types of water in their tank: saline water and fresh water.
You can get saline water from a specialist pet store – the water used for saltwater fish will be okay. Alternatively, purchase salt from this store and mix it with distilled or spring water.
Saline water stimulates a hermit crab’s sense of smell, encouraging them to eat. The presence of saltwater helps hermit crabs feel more comfortable in captivity as it reminds them of their natural environment.
Never apply table salt to water for hermit crabs. While popular opinion declares that the iodine in table salt is harmful to hermit crabs, it’s the anti-coagulation agents added to the iodine that causes health problems. Either way, avoid table salt.
Freshwater will also be used for bathing and drinking. While only one species of hermit crab – Clibanarius fonticola – lives in a freshwater environment, they’ll use freshwater to balance the salinity level in any water carried in the shell and skin.
Can You Give Hermit Crabs Tap Water?
Never place unfiltered tap water in a hermit crab tank. Tap water contains chlorine, which causes a hermit crab’s gills to blister, reducing the ability to breathe and eventually leading to suffocation.
Bottled water is the safest choice if you can’t dechlorinate tap water.
Tap water also contains trace heavy metals, especially copper. The negative impact of copper on hermit crabs’ health takes longer to manifest but can be just as dangerous.
As per Oecologia, copper exposure also makes hermit crabs twitchy and easily startled.
Instead, get a water purifier or distill the water. To achieve the latter, boil tap water until it turns to vapor, which will eventually condense back to water devoid of heavy metals or chlorine.
Besides the time and effort involved, the problem with distilled water is that it rids the water of as many positive minerals as negative elements. Hermit crabs won’t enjoy the calcium and magnesium found in water, which is another argument in favor of bottled water.
How Do Hermit Crabs Drink Water?
Hermit crabs have 3 sets of small mouth parts called maxillipeds, which are used for eating and drinking. Watching a hermit crab closely may also see it using the maxillipeds to groom itself, especially after eating or drinking.
When a hermit crab wants to drink water, it’ll get as close as possible to the water source, usually climbing inside. It’ll lower the mouth until the maxillipeds are dipped into the water. The maxillipeds then lift the water into the mouth.
As you can imagine, this isn’t the most efficient way of drinking – at least some water will be dropped and lost in the process. This means that, even if a hermit crab appears to be spending quite some time in a water bowl, it’s only consuming a handful of sips of water.
Do Hermit Crabs Gain Water from Food?
Fresh fruit and vegetables are fundamental to hermit crab diets, and you can vary their meals. Fruits and vegetables with high water content provide additional hydration.
Foodstuffs that are high in water and hermit crab-safe include:
- Apples (remove the pips first.)
If the hermit crabs eat these foods, they’ll benefit from the water within and gain other health benefits, but solid food shouldn’t be considered an adequate substitute for drinking water.
Do Hermit Crabs Drink Water from Sponges?
Some hermit crab owners keep sponges in an enclosure as an additional source of hydration, moisture, and even an emergency shell. A wet sponge in a tank will maintain humidity and allow the hermit crabs to drink if a water dish is occupied.
Sponges are an optional extra, not a sole water source. They must also be removed and replaced every 48 hours, as sponges will attract bacteria and fungi that could harm the hermit crabs.
Seek specialist aquarium products if you use sponges for a hermit crab’s hydration needs. A generic kitchen or bathroom sponge may be created using chemicals and materials unsafe for hermit crabs.
Hermit crabs live in hot, moist conditions, so water is essential to their daily routine. Always assess the water level in the tank, replacing dirty water and topping up empty dishes at least once a day.