Why Is My Turtle's Shell Soft?

Baby turtles tend to have softer shells, and it can take years for a turtle to develop a fully grown hard outer shell. However, there is a possibility that your turtle has too soft of a shell; this happens when a turtle develops a metabolic bone disease, or it could signal that your turtle is not living in ideal or healthy conditions.

Having soft shells at a younger age could be a major killer of young turtles, particularly aquatic turtles. The main cause is Metabolic Bone Disease (MBD), which is caused by an unhealthy diet or scant lighting. You should know that turtles need a particular quantity of calcium within their blood. Below are some of the main reasons that your turtle get a soft shell.

Why is my turtle’s shell soft?

Keep in mind that a soft shell could be a sign of metabolic bone disease and shell rot. If it is not treated quick enough, it could become fatal. Some of the main causes of soft shell in turtles include calcium deficiency, unbalanced diet, poor lighting, and inadequate basking platforms.

Not enough calcium in their environment

Lack of minerals, particularly calcium, is one of the main causes of MBD and can cause your turtle to have a soft shell. While most turtle pellets contain calcium, there is still a chance your turtle is not consuming enough. If you suspect your turtle is not getting enough calcium, I recommend immedielty adding calcium supplements to their diet. One of the easiest ways to do this is to add these calcium blocks to your water.

calcium blocks for turtles

Sometimes people confuse calcium deficiencies with normal turtle shell peeling. You can learn more about the difference in my video below:

Nutritional Deficiency

There is a also a good chance that your turtle’s diet is effecting the hardness of their shell. Many owners wonder what do turtles eat? It is important to feed your turtle a consistent diet that includes both pellets and vegetables. You can read this article to learn more about how much to feed your turtle.

Sometimes, a turtle will just have a natural deficiency of certain vitamins that is caused by genetics or their environment. If this is the case, you should buy vitamin supplements to ensure your turtle is intaking all the proper nutrients.

UVB light

Turtles like to bask, and therefore the daylight helps to grow their bones and shells and keep them hard. In captivity, it is extremely important that you get a UVB light as soon as possible once you get your turtle. Failure to provide proper lighting for your turtle can cause a soft shell, and can also cause white residue to build on their shell.

A turtle can usually go a couple days without a proper light, but after that there will certainly be health consequences. You can buy a cheap UVB light here.

If you are having trouble getting your turtle to bask, you should watch my video below.

Basking spots

Turtles must exit the water to dry off entirely. In captivity, within the absence of natural sunlight,  basking is an extremely important activity for turtles. Being dry and absorbing light helps them absorb D3 which is very important for their diet. It is very important that you provide a basking spot that is easily accessible for your turtle. This means that it is not too steep, and also has enough grip so that your turtle won’t slip off.

You can learn more in my article about what an unhealthy turtle shell looks like.

How to prevent soft shell in turtles?

The best way to prevent soft shell in turtles is to ensure that your turtle has access to enough light, and also has enough calcium and phosphorous in their diet. Supplementation of minerals like calcium is an option. If your turtle is not frequently basking, you should considering getting a basking platform that is easier for your turtle to climb on.

Another important thing to note is that soft shell is frequently accompanied by weight loss. If you notice your turtle is losing a lot of weight, you should take action immediately.

If you continue to give your turtle the adequate amount of light and ensure they are intaking the proper minerals, they will likely become healthy and develop a hard shell. Another important aspect of maintaining a healthy turtle shell is to ensure that your tank’s water and air temperature is adequate for your turtle. In general, the water of your turtle tank should be between 75-86 degrees fahrenheight.

The air temperature should be about 10 degrees warmer than the water. You can easily monitor these temperatures by getting a thermometer for your tank.


When a turtle develops Metabolic Bone Disease (MBD), their shell begins to rot and become very weak. This can leave your turtle very succepptible to infections. If you follow the steps listed above and your turtle continues to have a soft shell and doesn’t look healthy, I recommend taking him/her to the vet.

The vet might prescribe special supplements or medicines to help cure your turtle of the problem. Most importantly, you should always check in on your turtle on a daily basis in order to ensure they are healthy and that they are living in healthy conditions.

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