Do Turtles Need Calcium?

cuttlebone for turtle

Turtles make a great pet. They are fun to care for and mesmerizing to observe. They are relatively low maintenance if you ensure the correct food and keep their habitat clean. Depending on the species, they have different eating habits. There are some proteins and nutrients which are essential for them. If deprived, it can cause serious illness to your beloved pet.

The turtles try to absorb all these proteins and nutrients naturally in the wild. As a turtle owner, you owe them to provide the best care and protection. You need to understand their needs and keep them in a safe environment. Ensure that they are not deprived of the nutrients and proteins they need.

In this article, we will learn about the calcium needs in turtles. Keep reading to know how important is calcium for turtles.

Related Article: How To Make Tap Water Safe For Turtles?

Do Turtles need calcium?

Yes, turtles need calcium. Calcium helps their bone and shell in getting stronger. The turtle’s shell needs extra calcium, so calcium intake is important to keep them safe. 

If we compare wild turtles and pet turtles, pet turtles are found to be more likely to suffer from calcium deficiency than wild turtles. A healthy turtle requires minerals, proteins, and other nutrients such as calcium, vitamin D3 and phosphorous for its overall development. A study suggests that turtle shells and bones need more calcium than any other animal.

How much calcium is required for the turtles?

Comparatively, baby turtles require more calcium than adult turtles. You can provide calcium-rich food and calcium supplements to your turtle for it to grow strong and healthy. Breaking cuttlebone and foods like milk thistle and dandelions are some of the common calcium supplements you can get at any pet store.

Alternatively, you can also check for calcium supplements on amazon. Below are my recommendations for best calcium supplements for your turtle. You can buy anyone of them depending on price and availability.

ProductPurchase Link
T-Rex Box Turtle Supplement – Calcium PlusBuy on Amazon
Dr.Turtle Slow-Release Calcium BlockBuy on Amazon
SunGrow Turtle Calcium Supplement Balls – Pack of 10Buy on Amazon
Emours Natural Cuttlefish Bone for Turtles – Pack of 2Buy on Amazon

1. Calcium-Rich Food

Food habits play a vital role in their health and better growth. You can provide crustaceans such as crayfish. They are found to be an important source of calcium for turtles. You can also provide them live food such as crickets and earthworms, which are a rich source of protein but make sure you do not provide too much of it.

To increase their calcium levels, you can provide your pet turtle mosquito fish, guppy and bluegill fish, etc. Providing them with calcium-rich food can help them stay healthy.

Try to give them green leafy vegetables. Green leafy vegetables like kale are rich in calcium. Most herbivorous turtles like eating vegetables, which can help them if they are suffering from calcium deficiency.

Another way you can help your turtle get enough calcium is by sprinkling calcium supplements on their food. It is in powder form, so sprinkling it on the turtle food is all you have to do. You can also put it in the water, and it will dissolve quickly.

You can provide commercial food to your pet turtles. It is rich in calcium and nutrients. You can also give shrimp to your turtles as it is an excellent source of calcium. Frozen and dried shrimp and krill have been long used and are readily available. Some turtle owners prefer calcium blocks and cuttlebone for their turtles to remain healthy.

2. Ultraviolet rays

Exposure to UV rays is equally important as a diet is for the turtle to absorb calcium. If your turtle is not exposed to sunlight, ensure that you provide proper lights so that the turtle absorbs UV rays.

For turtles to process and utilize calcium, they need a vitamin called D3. When the skin absorbs UVB rays, the body creates Vitamin D and converts it into Vitamin D3. Only if vitamin D3 is present, turtle begins to utilize the calcium they have taken in. Without absorbing UVB rays, turtles cannot produce Vitamin D3 and utilize calcium.

UVB and heat can be provided to your turtle through special lamps. You can check out our article on which lights you need to use for the turtle here: Can I Use A Regular Light Bulb For My Turtle?

Do Red-Eared slider turtles need calcium?

Yes, the Red-eared slider turtles need calcium. 

Although the Red-eared slider turtle is hard-shelled, it still needs calcium to keep its shell and bones stronger and healthy. They require proper nutrition, and they get it by a diverse and varied diet containing a balance of vegetables and animal protein, depending on the pet’s age.

Most veterinarians suggest that the red-rared slider turtle needs a balanced and commercially available multivitamin once per week with an additional source of calcium, such as calcium block or cuttlebone, twice per week.

How does the wild turtle get calcium?

The wild turtles are usually exposed to sunlight. Turtles get Vitamin D3 from sunlight, and they can utilize calcium by processing vitamin D3. The wild turtles also eat wild insects and plants. Turtles love eating live food, and they eat anything that is moving. They also eat crayfish and shrimp in the wild, which are a good source of calcium.

There is a cactus called Prickly pear found in the natural habitat of the Mediterranean turtles (Sothern Europe and North Africa) and the deserts of North America. It is a natural habitat of most box turtles. This plant contains a relatively high concentration of calcium( 56mg per 100g), an excellent source of other nutrients and hydration.

Besides plants and animals, the other primary source of calcium that the turtle may encounter in the wild is in the form of naturally occurring rock formations, particularly chalk or sandstone, which form as a result of animal decay over many millions of years. Turtles usually lick rocky outcrops or chew small rocks as they do it naturally.

Can turtles suffer from calcium deficiency?

Yes, turtles can suffer from calcium deficiency. Calcium deficiency not only affects the shell of the turtle but also impacts many other internal organs of the body. Softshell is the most obvious symptom of calcium deficiency in a turtle. 

Turtle’s shell becomes soft if there is a lack of calcium in their diet. Failure to provide calcium can also lead to metabolic bone disease. The symptoms include poor walking, lack of appetite, swollen lumps, softshell, etc. 

Lack of calcium increases the incidence of turtles becoming egg-bound. This happens when a female turtle is pregnant and cannot expel her eggs due to weak muscle contractions. It can be dangerous for your turtle. Symptoms include excessive straining and restlessness. If your turtle is facing this issue, you need to take it to the veterinarian.


Turtles require calcium to remain healthy and grow stronger. Pet turtles are found to be mostly suffering from calcium deficiency. Baby turtles require more calcium than adult turtles. It is essential to provide your turtle with calcium-rich foods such as crayfish, crickets, earthworms. You can also provide them with green leafy vegetables. There are calcium blocks and supplements available in pet stores that can keep your turtle healthy. Ultraviolet rays are very important for turtles as it provides vitamin D3 to them. You must provide your turtle with proper lights for them to absorb heat and Vitamin D3. Compared to pet turtles, wild turtles get enough calcium from plants and animals available in the wild. You need to check if your turtle is suffering from calcium deficiency and take it to the veterinarian if needed. The most common symptom of calcium deficiency is soft shells in turtles.