Why is My Water Turtle’s Shell Soft?

Eastern Box Turtle

Although young water turtles do generally tend to have a softer shell than adult turtles, a shell that is too soft could indicate a problem. A condition known as metabolic bone disease (MBD), or softshell syndrome, is a major killer of juvenile aquatic turtles. It is often caused by poor husbandry.

Without the right care and attention, water turtlesOpens in a new tab. can become quite ill. MBD can become an issue when the turtle is unable to absorb calcium in the bloodstream. When this happens, the calcium is drawn from the turtle’s bones (which includes the shell), making them soft and weak in the process. MBD can be fatal if left untreated, resulting in a slow and painful death for the turtle.

If you are considering a water turtle as a pet, or indeed have acquired one, and have noticed that its shell is quite soft, it is probably best to do some additional research into what these reptiles need for healthy growth.

Aquatic Turtle Tank Setup

Although it may first appear that a water turtle is going to be an easy pet to look after, the reality is quite a bit different. It is the job of the keeper to ensure that conditions match the turtle’s natural habitat as much as possible. This usually means providing both artificial heating and lighting as well as a tank that provides as much space as possible.

Aquatic turtles can grow to around eight inches or more and do require around one hundred gallons of water space to swim about in upon reaching adulthood. It may not seem this way when they are very small, and many keepers do make the mistake of buying a tank that will soon become inadequate. It is best to do your research regarding the type of aquatic turtle species you are buying and then buy a tank that will be suitable throughout its life.

You will need a tank that has both water and a ‘land’ area for basking. The tank will require artificial heat, with the water temperature kept at around 75F to 80F and the basking area as high as 95F. This means that you will need to invest in both a heat lamp and a water heater. You can buy these in a reptile store or online. Amazon supplies a great range. Click here to seeOpens in a new tab. (opens in a new tab).

Your aquatic turtle will also require around 10-12 hours of UV light per day to enable it to convert vitamin D2 to vitamin D3. This is necessary for the absorption of calcium, which is required to keep bones healthy.

Mississippi Map Turtle
Mississippi Map Turtle


Your aquatic turtle requires both meat and plantsOpens in a new tab. for good health, so varied diet is best. The more varied the diet, the more nutrition the turtle will get. You should provide a good mix of meat and plants, such as:

  • mealworms
  • earthworms
  • chicken
  • pork
  • shrimp
  • tuna
  • snails
  • crickets
  • romaine lettuce
  • squash
  • collard greens
  • mustard greens
  • melon
  • berries
  • apple.

Some people also like to offer turtle pellets, which is a commercial food source made specifically for turtles. Spinach should not be given to aquatic turtles though as it can affect the absorption of calcium, which could result in the development of MBD. This can be a problem even in turtles that are being offered calcium supplements.

On that note, it is important to mention the need for supplements. Your turtle should be provided with calcium supplementation regularly. This will help prevent MBD. If you are worried about your turtle’s shell being soft, it might be worthwhile getting a cuttlebone from your local pet store. If you are placing cuttlebone into your turtle’s tank, be sure to scrape away any sharp backing as this can injure a turtle. Cuttlebone helps to reverse any calcium deficiency that is causing the soft shell.


A softer shell is quite common among younger water turtles, but if you notice a soft shell in an older turtle or a drop in weight, it might be the result of MBD. If you are worried about your turtle, I recommend contacting a vet for expert advice. As with most things in life, prevention is better than cure, and in the case of MBD, this is easy to prevent but much harder to cure.

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I am a content creator by profession but exotic animals are one of my great passions in life. Over the course of my adulthood, I have had the pleasure of looking after stick insects, terrapins, an Egyptian tortoise, giant African land snails, a crested gecko, a Chilean rose tarantula, a couple of curly-haired tarantulas, and a selection of millipedes, centipedes and worms!

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