Cuttlebone is an oval-shaped skeleton of the cuttlefish, a marine cephalopod. When a cuttlefish dies, its skeleton floats to the ocean’s surface, often washing up on shore. Here, the cuttlebone will frequently attract the attention of wild hermit crabs.
Cuttlebone should be one of the first things you add to a tank if you’re keeping captive hermit crabs. Cuttlebone is primarily made of aragonite, a carbonate mineral that’s a rich source of calcium.
Calcium is the most critical of all components of a hermit crab diet, as they rely on this mineral to build and maintain a robust and sturdy exoskeleton. As per Marine Biology, the chelipeds and thorax are particularly enhanced by ingesting calcium.
Hermit crabs can enjoy cuttlebone in several ways. It can be placed in a cage whole, allowing multiple hermit crabs to nibble on the cuttlebone or grind it into dust and sprinkle it over food in a bowl.
Cuttlebone isn’t essential for hermit crabs, but if you’re not going to use it, look for an alternative supplement that performs the same role. Ground calcium carbonate is arguably the best option, but cuttlebone offers enrichment and nutrition.
Will Hermit Crabs Use Cuttlebone as a Shell?
According to Current Biology, the Pharoah cuttlefish sometimes disguises itself as a hermit crab in the wild. Hermit crabs are automatically attracted to shells that carry a scent of calcium.
This makes it possible that a hermit crab may look to wear a full cuttlebone as a shell, which will only work if a hermit crab lives alone. As hermit crabs are so drawn to cuttlebone, the desire to eat ensures that it’ll quickly become unsuitable as a protective layer.
Can Hermit Crabs Eat Cuttlebone?
Hermit crabs should eat cuttlebone regularly. Why is cuttlebone good for hermit crabs? As discussed, it’s due to the high calcium content. A typical cuttlebone is made up of around 85% calcium.
Calcium toughens up a hermit crab’s exoskeleton, reducing the risk of impact injury. Hermit crabs always need a steady source of calcium, but it’s even more pivotal during molting. If a hermit crab eats well, it stands a much better chance of surviving and flourishing.
Hermit crabs burn through calcium resources daily, so they must constantly be replaced. While leafy greens are an acceptable source of the mineral, hermit crabs grow bored if they eat the same food every day. Cuttlebone is the perfect supplementation, especially when paired with Vitamin D.
Vitamin D and Cuttlebone
Most readily associated with the rays of the sun, Vitamin D is vital to the processing of calcium within a hermit crab’s body. Without Vitamin D, calcium can’t be synthesized.
Hermit crabs are omnivores, so they can gain Vitamin D from their diet. Offer small quantities of red meat (especially liver), oily scaled fish, and egg yolks. Small servings of breakfast cereal can also provide hermit crabs with Vitamin D.
You could also get a UVB light for the hermit crabs’ enclosure, as this will provide a measure of Vitamin D for your pets. Ensure this doesn’t override the hermit crab’s need for a reliable variance of light and dark across the day and night.
Where To Buy Cuttlebone for Hermit Crabs
If you’re looking for cuttlebone, here are your options:
- Exotic pet stores
- Butchers and fishmongers
- Finding cuttlebone on the beach
Cuttlebone is essential to companion birds, so you’ll find it for sale in any pet bird store.
When browsing cuttlebone in a pet store, check the packaging carefully. The product should read as “washed and desalinated.” This means the cuttlebone has been treated and cleaned, removing potential bacteria that could harm hermit crabs.
If you purchase cuttlebone from a fishmonger, and certainly if you plucked it straight from the beach, it’ll not have undertaken this cleaning process.
Additionally, it’s impossible to know how long raw cuttlebone has been exposed to seawater. While the cuttlefish is marine-based, the shell is weakened by prolonged exposure to salty water.
How To Give Hermit Crabs Cuttlebone
Hermit crabs can be provided with cuttlebone whole or ground into food.
Placing the cuttlebone in the tank whole gives hermit crabs something to interact with, but the latter is ideal if they ignore the cuttlebone in the tank.
They’re unlikely to taste ground cuttlebone in their food but will benefit from additional calcium. If possible, grind the cuttlebone by hand by crushing it with a rolling pin. A blender will generate heat, which can remove some of the nutrition.
If you prefer to provide the cuttlebone whole, place it in the tank while the hermit crabs sleep. The cuttlebone could be laid down or stood upright on the substrate.
The scent of calcium should be enough to tempt feeding, but if not, spread a sweet taste like jam on the cuttlebone to encourage further investigation.
You could also try attaching cuttlebone chunks to a tank’s side. The walls will be solid, so this may be tough, but as hermit crabs love to climb, elevated cuttlebone will reward them for their physical efforts.
How Often Should Cuttlebone be Changed?
Cuttlebone won’t spoil, soften, or rot in the warm environment of a tank. Provided the cuttlebone isn’t soaked in salty water, it should remain sturdy for as long as it takes hermit crabs to eat it.
If your hermit crabs usually respond positively to cuttlebone but show no interest in a new addition, consider changing it immediately. It’s unlike hermit crabs to show such consternation – the cuttlebone may contain something toxic or otherwise harmful.
How Much Cuttlebone Do Hermit Crabs Need?
There isn’t any such thing as “too much cuttlebone” for hermit crabs.
Your pets won’t eat more than they can cope with, and it’s unlikely that cuttlebone will spoil their appetite and prevent them from enjoying a balanced diet.
Including more than one cuttlebone resource in a tank is advisable. As per PloS One, while hermit crabs are typically docile, they may grow competitive and territorial over food.
Unfortunately, there are no guarantees of how hermit crabs will react to cuttlebone. Most will go crazy for it and immediately start to eat, while others may ignore the cuttlebone or show fear toward it.
Alternatives to Cuttlebone for Hermit Crabs
The closest like-for-like alternative to cuttlebone for hermit crabs is oyster shells. You’re unlikely to find these for sale in pet stores, but many online resources are available. Like cuttlebone, oyster shells can be consumed whole or ground into food.
Another choice is to use calcium carbonate. This is usually sold by health food shops in powdered form, which can be sprinkled into food in much the same way as a ground cuttlebone. Serve this two or three times a week in a dish or bowl.
Calcium blocks are another option. These tend to be smaller than cuttlebone and may cause more conflict as they resemble conventional snacks. Calcium blocks come in various scents and flavors, so they may be more appealing to fussy hermit crabs.
You can try to provide hermit crabs with all the calcium they need through food, but this is a substantial risk. You may not notice that your hermit crabs lack fortification in their exoskeleton until it’s too late, and by this stage, irreversible damage may be done.
