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3 Reasons For White Spots on a Turtle’s Shell

White spots on a turtle’s shell are a common problem, but fortunately one that can be easy to resolve. Appearing as either small patches or large areas, white spots can also be present on the neck and legs. In general, they have three main causes: mineral deposits, shell rot, and shedding of the skin and scutes.

The problem is that these issues can be difficult to tell apart, and it’s important to determine what you’re dealing with before taking any action. In this article, we’re going to give you detailed advice on how to identify, treat and prevent each of them. We will also tell you when to seek the help of a vet.

White Spots on a Turtle’s Shell

1. Mineral deposits

Red eared sliders - large one with mineral deposits
Red eared sliders – large one on bottom has mineral deposits

Something you may notice in your pet’s tank is white deposits accumulating on any area of glass that water has dried on. If this is the case, chances are you have hard water. Hard water contains high amounts of calcium carbonate and magnesium. Whilst neither of these do any harm to your pet, calcium carbonate dries onto the shell when the animal leaves the water and takes on a white, chalky appearance.

A turtle with mineral deposits on its shell almost always has large areas that turn white, rather than just the odd spot here and there. Often it is the top half of the shell, called the carapace, that turns white because it is out of the water more.

If your turtle has large areas of its shell turning white, but shows no symptoms of poor health, then it probably is due to mineral deposits. To be sure, take some vinegar and apply it to one of the white areas. If calcium carbonate is the cause, then the acetic acid in the vinegar will produce a strong fizzing reaction. This does no harm to the turtle and gives you a clear indication that hard water is at fault.

How to treat mineral deposits:

  1. Stay calm! Mineral deposits are harmless and can be dealt with at home.
  2. Mix vinegar (or apple cider vinegar) with water to make a 50:50 solution.
  3. Remove the turtle from the water and let it dry.
  4. Gently scrub the turtle’s shell using the solution on a soft toothbrush. Make sure you don’t get it in the eyes!
  5. Let the turtle dry again, then put it back in its enclosure.
  6. Repeat twice in the first week, then only once a week until the deposits are gone.

How to prevent mineral deposits:

  1. Use a water softener pillow in your filter. These remove some of the calcium carbonate.
  2. Use aquarium water conditioner solution.
  3. If you can’t get a hold of the above options, use a household jug filter to condition your pet’s water. This does work but takes a long time for a big tank!

When to see a vet:

There is no need to see a vet for mineral deposits. Only contact a vet if you feel that they are getting worse and are concerned they may be something else.

2. Shell rot

Red eared slider with shell rot
Red eared slider with shell rot

Shell rot refers to a bacterial or fungal infection of the shell and is also commonly known as ulcerative shell disease. Though it can take on a different appearance according to the pathogen causing it, shell rot almost always starts with small patches and spots, rather than the large areas that are seen with mineral deposits. Over time these spots grow wider and cause other changes, such as bright red areas, bleeding, mushy areas, dents, and pitting.

Unlike mineral deposits, shell rot is a serious condition that spreads down into the underlying bone, rather than just across the surface. If left untreated, shell rot will eventually lead to septicaemia and death.

Identifying shell rot can be tricky, but your best bet is to look at the shape and colour of the white patches. Are they uneven? Do they have pits or small holes forming next to them? Are some of them turning pink/red? If the answer to any of these is yes, shell rot is a strong possibility.

Another test that will help you decide is the scrape test. Use something like a ruler (not a knife!) to gently scrape the patches. If shell rot is present then it usually releases a foul odour, not unlike sewage or old gym socks.

How to treat shell rot:

  1. Double check your temperatures and make sure your pet has a basking area that allows it to dry off completely.
  2. Scrub the affected areas gently with a toothbrush and lukewarm water to remove any dirt.
  3. Let the shell dry.
  4. Apply povidone iodine or silver sulfadiazine ointment to the affected area. Let dry for an hour before returning the turtle to its enclosure.
  5. Repeat daily for three weeks, keeping a photo log to make sure it’s working.
  6. Change out the water and your filter media regularly.

How to prevent shell rot:

  1. Make sure the enclosure is safe. Shell rot can occur from cuts or abrasions, making enclosure safety essential. Your pet needs to be able climb in and out of the water without encountering anything rough or sharp.
  2. Maintain good water hygiene. Change your pump media regularly and consider buying a pump with a built-in UV steriliser.
  3. Read the full Shell Rot article for a more in depth look.

When to see a vet:

If pits, dents, mushy areas, bleeding, or discharge occur, see a vet immediately. This means that the infection is beyond the point where home treatment could be affective.

3. Shedding of the skin and scutes

Red Ear Slider shedding healthily
Red Ear Slider shedding healthily

There are two types of shedding that we need to know about as turtle enthusiasts: ecdysis and dysecdysis. Ecdysis is normal shedding, whereas dysecdysis is abnormal shedding.

All turtles shed their skin, and most aquatic turtles also shed their scutes. This renewal of the outer layer of keratin allows for growth, but also helps slough off algae and dirt. After ecdysis, the new shell or skin should be bright, colourful, and clean.

Scutes that are shed are paper thin, and come off in a single, almost transparent layer. Skin that is shed can come off in small pieces or strips – resembling white string or cotton-like material.

Sometimes healthily shed skin can hang off the neck or limbs and float while the turtle is submerged. In this case it looks like white or grey patches, but is extremely thin, and not particularly visible when the animal is dry. While scutes are shedding they may take on a whitish appearance while underwater – but if you look closely, this is due to trapped air. In this case they will be slightly metallic, not chalky, or mushy.

Dysecdysis of the scutes or skin can occur for many reasons. Whatever the cause, it presents differently from ecdysis. Dysecdysis tends to be in patches rather than across all an animal’s skin or shell. Dysecdysis of the skin can cause thicker layers to come off. Eventually it always leads to other symptoms, such as those for shell rot, or patches of red/bleeding skin.

Remember, young Diamondback Terrapins (Malaclemys terrapin) under 5-6 inches (12.5 – 15 cm) do not shed scutes. Softshell and Fly River turtles never shed scutes – only skin.

How to treat ecdysis:

  1. Do nothing! This is a natural process and the sign of a healthy, growing turtle. You can remove shed scutes from the water to help maintain hygiene, but never try to pick at them whilst still attached to your turtle’s shell.
  2. Remember, ecdysis of the scutes may take as long as 5-6 weeks for an adult turtle.

How to treat dysecdysis:

  1. For dysecdysis of the shell, try to determine how deep it goes and how widespread it is. If it is just a couple of layers, follow the prevention measures below and make sure the animal has access to UVB light – it may resolve itself.
  2. Occasionally, dysecdysis of the skin can be caused by bacterial or fungal infections, in which case the treatment for shell rot can help.

How to prevent dysecdysis:

  1. Maintain optimum basking spot and water temperatures. Overheating appears to cause dysecdysis in some species.
  2. Research the specific diet of your turtle species. Dietary imbalance is a common cause of dysecdysis of the scutes. Vitamin C or A deficiency can make turtles more susceptible to skin and shell problems, as can overfeeding and excessive protein intake for some species. Be aware that some turtle pellets contain more protein than others: check this when deciding on how much other animal protein to give your pet.

When to see a vet:

As I mention earlier, ecdysis is healthy and normal. No veterinary treatment is required. Dysecdysis, on the other hand, can be hard to resolve without tissue cultures and blood tests to determine its root cause. My advice is to seek a vet immediately if you notice flaking scutes that look like pastry, or red, sore patches on the legs or neck.

Wrapping up

In most cases, white spots on a turtle do turn out to be either mineral deposits or shedding. If your turtle has white spots, your first step should be to read through the sections above and decide which of the problems is occurring. After that you can decide whether it is something you can take care of yourself.

Remember, these tips are for home treatment on animals which are otherwise acting perfectly healthy. If any other symptoms are present alongside the white spots, such as lethargy or lack of appetite, don’t try to resolve the issue yourself – go to a vet immediately!

Thanks for reading. As always, comment or get in touch for more advice!

See our turtle first aid section for more health guides.

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Sunday 1st of January 2023

one of our 3 red sliders perished . we noticed white spots on a tank mates back ??? is this treatable and what is the disease .thanks


Monday 18th of October 2021

Mine has slight discoloration but his shell isn’t all one color and it’s light like the lighter color of his shell. He now has polka dots small white ones… I wipe him off when I clean his tank every month and noticed the shell color changing a bit but the dots are new. The dots are small like freckles or splattered white paint like people do for stars. I don’t know if they are able to come off or not I don’t mess with him randomly. He’s an African side neck turtle he’s been with me for almost 3 years now.


Thursday 24th of June 2021

my turtle doesn’t have any of the conditions listed above, but she has white stuff on her neck and shell, idk what to do. can you help?