A tortoise that changes color in patches, especially over a relatively short period, usually has a sickness, infection, or disease.
However, there are times when a gradual full-bodied color change is normal. So, note what color the tortoise is becoming and if it’s acting differently or strangely.
Skin slowly darkening or turning black is a natural sign of aging. However, if the skin darkens in patches, the substrate is unclean or causes irritation.
If the tortoise’s skin is turning white, it’s shedding its skin or has an infection.
If the skin turns red, this can mean parasites (ticks or mites). If there’s a red fluid below the scutes, this indicates shell rot.
If a tortoise’s skin turns yellow, this can be due to poor diet, liver failure, or jaundice.
Tortoise Skin Turning Yellow
If a tortoise turns yellow suddenly, check for these conditions:
Jaundice
This is a skin condition that is caused by instability in the liver.
Jaundice can occur in these ways:
- Obstruction of the bile duct.
- Liver disease.
- Excessive breakdown of the red blood cells in the liver.
These will cause the skin to turn yellow.
According to the Association of Reptilian and Amphibian Veterinarians, liver disease can be difficult to diagnose in tortoises until its symptoms have become severe.
Liver Failure
Alongside jaundice, a symptom and an issue of its own, a tortoise may have acute liver failure.
The tortoise turns a sickly yellow and:
- Suddenly becomes lethargic.
- Won’t eat its meals.
- Doesn’t move around.
Other signs of chronic liver disease include:
- Reduced weight gain or significant weight loss.
- Brumation issues, including post-hibernation anorexia.
- Changes to fecal matter and skin color.
Poor Diet
A tortoise may have too much fat or protein in its diet. Degenerative liver disease is usually caused by poor nutrition and excess fat.
Improving the tortoise’s diet is always recommended. Allow the tortoise more time to bask under UV light, which can boost its metabolism and immune system.
Tortoise Skin Turning Black
When you see a tortoise’s skin turn black, it’s natural to assume the worst. However, tortoises rarely get gangrene or other serious conditions responsible for blackening skin.
Here’s what causes tortoises to turn black:
Age
A natural reason for tortoise skin darkening is age. If the tortoise used to have a lighter carapace or skin, which darkened over time, this is a sign that it’s aging as it should.
Some tortoise species, including the Russian tortoise, will have naturally dark skin pigmentation, which will intensify as they age and may appear to turn black.
Substrate Irritation
This darkening skin should occur all over the tortoise’s body and not be centralized in one area. If you see only the underside of the tortoise starting to darken, it may be irritated by the substrate in its enclosure.
All tortoise enclosures should have a non-toxic substrate that can be ingested without harming its digestive tract. This substrate should retain moisture, so the skin doesn’t dry out and flake off.
Infection from Substrate
If you fail to clean out the substrate, the tortoise is more susceptible to infections, and these can manifest as darkened irritations or abscesses under its carapace.
Abscesses need to be surgically removed, or you’ll risk pus and bacteria building up around the wound.
Tortoise Skin Turning White
Of the different tortoise color changes, whitening skin is the most common, naturally turning white every few months. Here are the causes of white skin in tortoises:
Shedding
If the tortoise’s skin fades to a lighter color or turns white, this can mean it’s preparing to flake off.
As with all reptiles, tortoises shed their skin every few months to allow for new growth. However, this won’t happen in large strips or all at once. Instead, tortoises shed their skin in patches.
This is excess skin if you see flaky white parts on your tortoise. Don’t pick off these flakes, as doing so could harm the tortoise.
If you’re concerned about skin flakes, bathe the tortoise in shallow and warm water. Also, allowing the tortoise to bask under UV light more often can dry out its old skin and allow it to flake off.
A tortoise will shed parts of its shell, and it’ll start by losing color and making the tortoise’s shell appear duller than before. Let the tortoise shed naturally.
According to the Smithsonian Museum, these discarded scutes will leave behind rings like those on a tree, so you can estimate how old a tortoise is based on them.
Skin Infections
There are cases when white skin indicates an infection or fungus growing on its skin or shell. The best way to tell the difference between these conditions and shedding is by monitoring the tortoise’s behavior.
A shedding tortoise won’t show signs of distress or lethargy. Shedding tortoises may bask more often, but they should eat, drink, and play in their enclosure as usual. If the tortoise has an infection, it’ll:
- Fail to eat.
- Lose weight.
- Have abscesses on the skin.
If the tortoise has a fungal infection, this can appear as white or gray along the skin.
Red Markings on Tortoise
If you see red fluid directly underneath the scutes of the shell, this can signify shell rot.
However, this red fluid isn’t enough to cause a tortoise’s skin to turn red. Indeed, prominent red markings usually indicate parasites.
Tortoises turn red for these reasons:
Shell Rot
Shell rot is a Metabolic Bone Disease (MBD) that usually affects older tortoises.
This can occur due to fungal or bacterial infections, where bacteria enter the bloodstream. Shell rot causes the shell to slowly deteriorate and other severe health conditions.
A lack of or imbalance of nutrients, such as calcium or phosphorus, can cause shell rot. Bacterial, fungal, or algae infections damage the shell the most, and these infections can get under the carapace, attack the tortoise’s skin, and infect the bloodstream.
This blood infection is called septicaemic cutaneous ulcerative disease (SCUD). Bacteria in the blood can attack a tortoise’s vital organs, which can be fatal. This can be treated with vet-administered antibiotics.
The warning signs include:
- Unpleasant discharge or smells concentrated around the affected area.
- Reddish fluid under the scutes of the shell.
- Softening, lifting, or negatively impacting the carapace and scutes.
If the tortoise’s carapace starts flaking off, clean it twice a day with a povidone-iodine or chlorhexidine solution. Even if the tortoise is shedding, this can remove its old skin faster without issues.
Parasites
Red markings on a tortoise can indicate ticks, mites, or other external parasites.
Ticks and mites cluster where the tortoise’s skin is the thinnest. That’s why most will develop small lesions or cuts around these areas. Then, parasites lay their eggs inside the cuts.
Ticks or mites are black or red and so small that they’re hard to detect. They’ll burrow themselves in or around the tortoise’s upper legs, neck, head, or other crevices that are hard to reach.
