Why Is My Tortoise’s Shell Soft? (How to Solve and Prevent)

Strong shells are essential for a healthy tortoise, whether it lives in an enclosure or in the wild. If you find your tortoise’s shell is soft, it means that it’s suffering from metabolic bone disease.

A soft shell is usually caused by metabolic bone disease, which is caused by the lack of calcium in its diet, or by poor lighting, which can prevent the proper absorption of calcium. A soft shell can usually be fixed by increasing the amount of calcium you feed your tortoise.

So the problem is either the lack of calcium or the lack of UVB light, which allows tortoises to process the calcium. A soft shell can also be caused by a disease or an infection, but those cases are very rare and have other easy-to-spot symptoms. And we will talk about them. But first, let’s talk about the most common problem. The lack of calcium.

Calcium Prevents Soft Shells

There are three main ways in which a pet tortoise can get calcium, the first one is through vegetables, the second one is through supplements like cuttlebone and calcium powder, and there are also pellets. And each one of them has its own advantages and disadvantages.

Calcium From vegetables

Vegetables are an amazing food, they have a lot of vitamins, they have fibers, and they have calcium, it might seem that there is no downside to them. But there is one, and it’s quite big, and that disadvantage is that they have phosphorus.

Phosphorus is what gives tortoise shells flexibility, which is great because this little extra flexibility makes them more resistant to bites and other types of impact. But too much phosphorus can also make the shell a lot softer, and fragile, which is not good, even if there are no predators to take advantage of this weakness of the shell, it will affect the overall health of your tortoise.

Most vegetables have a calcium to phosphorus ratio, this ratio can be 1:1, 2:1, 5:1, 1:2, etc.

A 1:1 ratio means that the amount of calcium is equal, or almost equal to the amount of phosphorus. So a vegetable with this ratio is not that great for tortoises, but it’s not harmful either. But if possible such a vegetable should be avoided.

A 1:2 calcium to phosphorus ratio is really bad, there are not many vegetables with this ratio, so don’t worry too much about them. Just remember that if a vegetable has more potassium than calcium you should keep it away from your tortoise.

A 2:1 ratio is great, and this is what you should be aiming for, if the ratio goes higher it’s ok, but ideally this is the ratio that you are looking for.

At the end of the article, I will post a table with some of the most common vegetables that you will find in a supermarket and their calcium to phosphorus ratio.

Calcium From Pellets

Tortoises don’t really need to eat pellets, usually, fruits and vegetables alone are good enough. But they can be a great way to add some extra nutrients to their meals.

There are different types of pellets. Some are for turtles, others for tortoises or land turtles as they are sometimes called. You want to get the pellets that are for tortoises. Turtles are omnivorous, which means that they also eat meat, besides fruits and vegetables, so they have different dietary needs than tortoises, which don’t eat meat.

As for which pellets to get, the most reputable brands like Fluker’s, Zoo Med, and Exo Terra, should be good. I for one have been giving my tortoises Fluker’s Tortoise Diet, Small Pellet Food – Land Turtle Formula, which has 2.25% calcium. So, it definitely helps if your tortoise lacks calcium.

Calcium From Supplements

Giving your tortoise vegetables and fish is a great way to increase their calcium intake, but in most cases, this is not enough, and you should also give them some supplements.

The most common types of supplements are cuttlebone and calcium powder.

For cuttlebone, I have a dedicated article which you can find right here: Cuttlebone for Turtle (Beginners Guide + Buyers Guide). Some of the key points are:

• Remove the back part of the cuttlebone
• Break the cuttlebone into pieces that are the same size as the head of your tortoise
• You should give your tortoise cuttlebone once every two weeks
• Cuttlebone comes from fish, so all cuttlebone is the same

If your tortoise doesn’t show any interest towards the cuttlebone, then you still have one more option, calcium powder. Calcium powder, just like cuttlebone, is a supplement. But the way you use it is a little bit different.

The best way that I’ve found to use calcium powder is to take a plastic bag, put some calcium powder in it, add some pellets or small pieces of vegetables, and then add some water, so the calcium sticks to them, and then feed the pellets to the tortoise one by one. The reason why you don’t want to give your tortoise all the pellets at once is that the calcium can dry off and fall on the ground.

If you look for calcium powder for reptiles you will notice that there are two types, one with vitamin D3 and one without D3.

Vitamin D3 allows your tortoise to assimilate and make use of the calcium that you are giving it. Without D3 all that calcium won’t do anything. D3 usually comes from the sun, or from the basking area, in the case of pet tortoises.

So even if you get calcium powder with D3, you still need to make sure that your tortoise has a proper basking area from where it will get all the D3 that it needs.

Vitamin D3

Tortoises get their D3 from the basking area, which should be equipped with two light bulbs, one that provides heat, and one that provides UVB light.

The UVB bulb is the one that replicates the effects of the sun and provides vitamin D3 for your tortoise.

Both bulbs are very important for the health of your tortoise and need to be placed in a certain way in order to be effective. If the bulb is too far, its effects will be diminished. If the bulb is too close it can lead to burns or other health problems.

In the article Best Tortoise Light Bulb (Illustrated Buyers Guide) I have an in-depth guide on how to choose the correct wattage and how far you should place it from your tortoise. Here is a short extract about the UVB bulb, the one that is responsible for vitamin D3.

When it comes to choosing UVB bulbs things are a little more complicated due to the huge variety of wattages, in which UVB bulbs can be found. And then there is the fact that most manufacturers have a different rating system, and some of them have no instructions at all.

So, for UVB bulbs, I am going to give you the exact distance for a few bulbs that I’ve used before that come from a reputable manufacturer, and I will provide links to Amazon, where you can get them

And in case you have something between the UVB bulb, like a net, or a grill, you want to move the bulb closer by one inch, as anything in between the tortoise and the bulb will reduce the amount of UVB rays.

One more thing to keep in mind is that UVB bulbs will stop producing UVB rays, way before they will stop producing light. On average I would say that a UVB bulb only produces UVB rays for only half of its lifespan. I measured the amount of UVB light produced by the bulbs and noticed that after about 6 months, the amount drops considerably, so I change my light bulbs at around 6 months, and I would advise you to do the same.

And if you want to measure how much UVB light your bulb produces you can use this device. While it’s a little bit expensive, overall it will save you money since you will know exactly when the bulbs run out of UVB light, and it will help your tortoise remain healthy. But it’s not a requirement.

Can You Give Your Tortoise Too Much Calcium?

Technically speaking, too much of anything can be dangerous, so yes you can give your tortoise too much calcium, but practically speaking you would have to give your tortoise absurd amounts of calcium in order to affect its health. So, unless they eat a bag of calcium supplements per week, you shouldn’t have to worry about this.

As long as you don’t go overboard with it, there should be no problem.

How Much Calcium Should I Give My Tortoise?

There is no set amount of calcium that you should give your tortoise. As I said, the main thing that you should be careful of is not overdoing it.

Here is how I give my tortoises extra calcium.

I feed my tortoises a small amount of vegetables once every two weeks, and 2 fish once per month. And once every two weeks I give them a small piece of cuttlebone. For the tortoises that don’t like the cuttlebone, I use calcium powder. All this while giving their regular meals (pellets) once every 3 days.

The only time I skip giving them pellets is when I give them fish, as the fish should be more than enough to replace the pellets.

I’ve been doing this for quite a few years, and my tortoises are as happy and healthy as they’ve ever been. So I would recommend you to try this routine or a similar one.

The Age of the Tortoise

All young tortoises have a soft shells. Tortoises are born with a relatively soft shell. And it will remain that way until they reach adulthood.

When a tortoise reaches adulthood depends on its species. Some reach it after 2 years, some after 8. Some after 30. The simplest way to tell if your tortoise is an adult or not is to measure it. Tortoises are considered adults when they reach a certain minimum size.

So, google “your tortoise species” average size. If your tortoise is far from that size, tha it’s still growing and it’s perfectly normal for its shell to be somewhat softer. The closer a tortoise gets to maturity, the harder its shell becomes.

Health Problems

One more possible reason why the shell of your tortoise is soft is a health problem.

There are quite a few possible health issues that can make the shell become soft. Some of them can be easily spotted, while others can’t.

One of the worst conditions that can easily be spotted is shell rot.

Shell rot is a disease that affects the shell from the interior and works its way to the exterior.

Shell rot is usually accompanied by one or more of the following signs:

• Strange indentations in the shell.
• White spots on the shell.
• Pink Spots. In severe cases, the white spots will start to become pink and you will be able to see the flesh underneath the shell.
• Soft spots in the shell in general.

If you spot any of those symptoms, you should go with your tortoise to the vet. Shell rot is not a disease that you want to mess around with.

And in fact there is none that you want to mess around with. So whenever you notice that there is something wrong with your tortoise I would advise you to also get the opinion of a vet.

Final Thoughts

A soft shell is caused by a lack of calcium, so the best way to treat and prevent it is to make sure that your tortoise has enough calcium in its diet and that it can properly use it.

There are multiple calcium sources: vegetables, fish, and supplements. And it’s a good idea to combine them, and not rely on a single one, since each of them has multiple health benefits, aside from providing calcium.

And don’t forget that calcium on its own won’t do anything, tortoises also need vitamin D3 to properly assimilate and use the calcium. Vitamin D3 comes from the sun, or in the case of pet tortoises, from the basking area. So make sure that your basking area is in order, otherwise, all the extra calcium won’t do anything.

And I would also advise you to go visit a vet with your tortoise. A soft shell is definitely not a good thing, and while doing everything in this article should solve the problem and prevent it from happening, there is a possibility that the problem might be more complicated than this, so it’s better to be safe.

I hope that this article answered all of your questions, but in case there is anything else that you would like to know, don’t hesitate to use the comment section below, and leave your question there. I will answer it as soon as I see it.

Here is a list of some of the most common vegetables and their Calcium to Phosphorus ratio:

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