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Why Is My Turtle’s Shell Soft?

Nicole Cosgrove

The turtle’s shell provides ample protection for its delicate body within. Whether the turtle is in a tank or in the wild, strong shells are a must for a healthy turtle. If you notice your turtle’s shell is soft, your turtle is likely unhealthy and needs attention right away.

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

To find out more about why your turtle’s shell is soft, as well as tips for what to do about it, keep reading. In this article, we fully explained the five most common reasons for a soft turtle shell, metabolic bone disease, and more. Let’s get started.

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What Is Metabolic Bone Disease?

As we learned above, metabolic bone disease is the most common reason for a turtle with a soft shell. What exactly is this disease, though?

Metabolic bone disease is whenever the turtle’s skeletal structure, carapace, and plastron are weakened because of a calcium and phosphorus imbalance. Calcium is highly important to many creatures, but especially turtles. It acts as a biochemical messenger that performs 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.

Turtles are just one animal that can experience metabolic bone disease. Nearly all reptiles are especially prone to developing this disease and require additional calcium to remain healthy.

5 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 very young and has a soft shell, there is nothing wrong with this turtle. Continue taking care of your turtle as you have been, and make sure to provide the turtle with ample nutrition, lighting, and clean environments to continue growing a hard shell.

baby turtles in the water
Image Credit: Pixabay

2. Calcium deficiency.

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

Metabolic bone disease is often caused by lack of materials, especially calcium, in your turtle’s bloodstream. Even if you feed your turtle pellets that contain calcium, your turtle may not be getting enough. You can supplement more calcium into your turtle’s diet to ensure 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, they absolutely need a UVB light to ensure there shell remains hard and healthy. Lack of UVB lighting is likely to blame if the turtle’s soft shell is accompanied by a white residue.

Additionally, you have to add basking spots for your turtle. Basking lights allow turtles to dry and absorb D3. Without a basking spot, your turtle can have nutritional deficiencies, which leads to metabolic bone disease, as we have already learned.

turtle inside aquarium
Image Credit: 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.

Finally, the last potential reason that 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.

leaves divider leafWhat To Do If Your Turtle Has a Soft Shell

Because a hard shell is required for your turtle to remain happy and healthy, you need to act quickly if you notice 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 is not to blame for your turtle’s soft shell, diet and nutritional deficiency likely is. Supplement more calcium into your turtle’s diet. Even if the temperature or light within the tank was 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 blame for a soft shell, we learned that bacterial infections can also cause a soft shell. If there are no other signs of metabolic bone disease and the soft shell is accompanied with oddly colored patterns, see your vet to get antibiotics to treat the bacterial infection.

When To 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 a company by rapid weight loss, take your turtle to the vet immediately.

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Final Thoughts

Unless your turtle is a baby, you should be alarmed if you notice 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, poor lighting, or poor temperature. The soft shell could also be caused by a bacterial infection.

In all of 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.


Featured Image Credit: Mark_Kostich, Shutterstock

Nicole Cosgrove

Nicole is the proud mom of Baby, a Burmese cat and Rosa, a New Zealand Huntaway. A Canadian expat, Nicole now lives on a lush forest property with her Kiwi husband in New Zealand. She has a strong love for all animals of all shapes and sizes (and particularly loves a good interspecies friendship) and wants to share her animal knowledge and other experts' knowledge with pet lovers across the globe.