Metabolic bone disease of the turtle
Metabolic bone disease is a very common disorder in captive tortoises, including the Greek tortoise (Testudo graeca). \nIt results from a lasting imbalance between calcium, phosphorus and vitamin D3, three elements essential to the strength...
What is it?
Metabolic bone disease is a very common disorder in captive tortoises, including the Greek tortoise (Testudo graeca). \nIt results from a lasting imbalance between calcium, phosphorus and vitamin D3, three elements essential to the strength of the shell and skeleton. \nOver time, the body draws calcium from the bones and shell to maintain normal blood levels, which gradually weakens them. \nThis disease is not contagious: it is directly linked to breeding conditions, in particular diet and exposure to light.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
The signs develop slowly, over several months, making them difficult to spot at first. \nThe shell may feel soft to the touch, especially at the edges (plastron) and become deformed, becoming bumpy or pyramidal instead of smooth. \nThe turtle may eat less, become less active and exhibit a stiff or hesitant gait. \nIn advanced forms, we observe difficulty moving, limbs that seem weak, swelling of the legs or jaw, or even an inability to lift oneself from the ground. \nFractures can occur with very light impacts, because the bones become brittle.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The main cause is a chronic lack of calcium in the diet, often aggravated by excess phosphorus (certain fruits and vegetables) and lack of exposure to ultraviolet UVB rays. \nThese UVB rays are essential because they allow the turtle's skin to produce vitamin D3, itself necessary for the calcium ingested to be absorbed by the intestine. \nWithout sufficient UVB or adequate calcium intake, the body compensates by drawing calcium directly from the bones and the shell.
Turtles kept indoors without a suitable UVB lamp or with lighting that is too old (the effectiveness of UVB tubes decreases over time) are the most exposed. \nA diet too rich in fruits, vegetables low in calcium or unbalanced in phosphorus also increases the risk. \nYoung growing turtles and breeding females, whose calcium requirements are higher, are particularly vulnerable. \nA lack of access to natural sunlight, especially during prolonged indoor wintering, also aggravates the situation.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian carries out a complete clinical examination, assessing the flexibility and shape of the shell, posture and mobility of the animal. \nX-rays allow you to visualize bone density and look for possible fractures or internal deformations. \nA blood test may be offered to measure calcium and phosphorus levels and assess the general condition of the turtle.
Treatment
The treatment combines a gradual correction of the diet, calcium and vitamin D3 supplementation under veterinary supervision, and the installation of suitable UVB lighting. \nIn painful or complicated cases of fractures, pain treatment or surgery may be necessary. \nThe correction must always be gradual, as a sudden increase in calcium can itself disrupt the body.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Prevention is based on three essential pillars: a varied plant diet rich in calcium (green leaves such as dandelion, mallow, clover), regular exposure to UVB light suitable for reptiles (or natural sunlight not filtered by a window), and calcium supplementation if necessary, under veterinary advice. \nIt is recommended to renew UVB tubes according to the manufacturer's recommendations, because their useful radiation decreases well before visible light weakens. \nA regular veterinary check-up makes it possible to spot the first signs before the deformations are irreversible.
Possible complications
Without treatment, the disease can progress to severe and permanent deformations of the shell and limbs, spontaneous fractures, partial paralysis, or serious problems such as impossible egg-laying in females due to a deformed pelvis. \nIn very advanced cases, the prognosis can be life threatening.
When to see a veterinarian
The shell appears soft, bumpy or deformed.\nThe turtle has difficulty moving, lifting itself or lies still.\nIt is eating significantly less or refusing to eat for several days.\nYou observe swelling of the legs, jaw or an abnormal gait.\nA fracture or deformation is visible or suspected.
Prognosis
The prognosis is favorable if the disease is detected early and dietary and light corrections are implemented quickly: young growing turtles can sometimes regain a normal shell. \nOn the other hand, deformities that have been present for a long time in an adult animal are often irreversible, even if the progression of the disease can be stopped.
Frequently asked questions
My Greek tortoise has a soft shell, is it serious?
A soft shell in an adult turtle is never normal and should be a warning sign. In very young individuals, a slight temporary flexibility exists, but any marked or prolonged softness warrants rapid veterinary advice.
Is a UVB lamp really essential indoors?
Yes, unless the turtle has daily, prolonged access to direct natural sunlight, without glass or plastic that blocks UVB. Indoors all year round, a reptile-specific UVB lamp is essential.
Can I give calcium to my turtle without veterinary advice?
A diet naturally rich in calcium is always beneficial, but targeted supplementation should be discussed with a veterinarian, as an excess or imbalance with phosphorus and vitamin D3 can also be a problem.
Can the disease recur after recovery?
Yes, if the breeding conditions (food, light) become unsuitable again. Regular monitoring and maintaining good practices are essential to avoid a relapse.
References
AVMA — American Veterinary Medical Association
Content reviewed by the TunisieVet editorial team · Updated 30 August 2026
Comments (0)
No comments yet.
AT A GLANCE
Need a veterinarian?
Find a practitioner near you on TunisieVet, with their specialities, hours and contact details.
Find a veterinarianAffected species
This information is provided for educational purposes only and is not a substitute for a veterinary consultation. If you have any concerns about your animal's health, consult a veterinarian.
Thinking of welcoming a pet? Dogs and cats are waiting for a family in Tunisia, and adoption is completely free.
Adoption listingsTo discover
Related diseases and linked Animalia content.
Infectious rhinitis of turtles (herpesvirus)
Viral
Ulcerative stomatitis of the turtle
Bacterial
Turtle intestinal parasitism (pinworms)
Parasitic
Intestinal parasitism in sea turtles (pinworms)
Parasitic
TunisieVet in your pocket 📱🐾 Access your veterinary services wherever you are. [ Download the app ]
Learn more