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Home > Turtles > Why Is My Turtle’s Shell Soft? Common Reasons & Care Tips

Why Is My Turtle’s Shell Soft? Common Reasons & Care Tips

Old turtle shedding its shell

A turtle’s shell provides ample protection for its delicate body. Whether the turtle is in a tank or in the wild, a strong shell is essential for its health. If you notice that your turtle’s shell is soft, it is unhealthy and needs attention right away.

Most likely, your turtle’s shell is soft because it has metabolic bone disease. This is often caused by poor diet or poor lighting, both of which can prevent the turtle from properly absorbing calcium. Without calcium, turtles can develop metabolic bone disease, leading to a soft shell. Alternatively, a bacterial infection could be to blame.

Here, we fully explain the most common reasons for a soft turtle shell and provide tips on what to do about it.


What Is Metabolic Bone Disease?

Metabolic bone disease is when a turtle’s skeletal structure, carapace, and plastron are weakened because of a calcium and phosphorus imbalance. Calcium is highly important to many creatures, especially turtles. It acts as a biochemical messenger in many pathways and transmissions.

Without the proper amount of calcium, your turtle’s shell and skeletal system will likely be soft. Additionally, the turtle’s muscles can have difficulty contracting, including in the heart. Turtles will also have the inability to form blood clots.

The turtle is just one animal that can experience metabolic bone disease. Nearly all reptiles are prone to developing this disease and require additional calcium in their diet to remain healthy.

The 5 Alternate Reasons Your Turtle’s Shell Is Soft

1. It is a baby

Many turtles are born with a shell that is relatively soft. This is completely normal, but you must take extreme caution when holding a young turtle. Most turtles won’t fully develop their shell until they have been alive for months, if not years.

If your turtle is a baby or otherwise very young and has a soft shell, there is nothing wrong with it. Continue taking care of your turtle as you have been, and make sure to provide it with ample nutrition, lighting, and a clean environment so they can work on growing a hard shell.

baby turtles in the water
Image Credit: Pixabay

2. It has a calcium deficiency

Once a turtle has fully developed its hard shell, the shell should stay that way until well after its death. If you notice that your adult turtle’s shell is becoming soft, it means there is an issue with your turtle’s health. Most likely, it is experiencing calcium deficiency, potentially leading to metabolic bone disease.

Metabolic bone disease is often caused by a lack of materials, especially calcium, in your turtle’s bloodstream. Even if you feed your turtle pellets that contain calcium, it may not be getting enough. You can supplement more calcium into your turtle’s diet to ensure that your turtle is getting enough to retain its hard shell.

3. The tank has poor lighting

Lighting plays a huge part in your turtle’s health. In the wild, turtles have abundant exposure to UVB light. Whenever turtles are kept inside, though, they need a UVB light to ensure that their shells remain hard and healthy. A lack of UVB lighting is likely to be blamed if the turtle’s soft shell is accompanied by a white residue.

Additionally, you have to add basking spots with lights for your turtle. Basking lights enable turtles to absorb vitamin D3. Without a basking spot, your turtle can have nutritional deficiencies, which can lead to metabolic bone disease.


turtle inside aquarium
Image By: zoosnow, Pixabay

4. The water temperature is too low

Water temperature plays a huge role in your turtle’s health. Turtle tank water should be between 75 and 86 degrees Fahrenheit. The air should be about 10 degrees higher. Keep a thermostat within the tank to monitor its temperatures.

5. It has an infection

The last potential reason your turtle has a soft shell is that it has some sort of an infection. Often, bacterial infections that go untreated weaken and damage the shell, as well as wreak havoc on other parts of your turtle’s body.

diamondback terrapin turtle
Image Credit: Miiko, Shutterstock

leaves divider leaf What to Do If Your Turtle Has a Soft Shell

Since a hard shell is required for your turtle to remain happy and healthy, you need to act quickly if you notice that its shell becoming soft. Here is what you should do if your turtle has a soft shell.

Determine the Cause

The first thing you need to do if your turtle has a soft shell is to determine the cause. If your turtle is a baby, that is likely the cause, and you don’t have much to worry about. For an adult, check the lighting system and temperature. If either of those issues are off-balance or not suitable for turtles, address them accordingly.

Supplement More Calcium

If lighting and temperature are not to blame for your turtle’s soft shell, diet and nutritional deficiency likely are. Supplement more calcium into your turtle’s diet. Even if the temperature or light within the tank is to blame, supplementing more calcium into the diet will help your turtle get back on track quicker. You may want to continue feeding your turtle more calcium even after the shell is healed.

Get Antibiotics

Although metabolic bone disease is more likely to be blamed, bacterial infections can also cause a soft shell. If there are no other signs of metabolic bone disease and the soft shell is accompanied by oddly colored patterns, see your vet to get antibiotics to treat the bacterial infection.

 See a Vet

If your turtle has a soft shell and fixing the tank and supplementing more calcium does not work after a few days, contact your vet. In the case that the soft shell is accompanied by rapid weight loss, take your turtle to the vet immediately.



Unless your turtle is a baby, you should be alarmed if you notice that your turtle has a soft shell. Most likely, your turtle is experiencing some form of metabolic bone disease as a side effect of poor diet, lighting, or temperature. The soft shell could also be caused by a bacterial infection.

In all these cases, you need to take extra care of your turtle. Supplement calcium into its diet, and take your turtle to the vet if necessary. If you don’t act fast, the damage could be irreversible or worse, fatal.

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Featured Image Credit: Pxfuel

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