The diet of most
turtles is, by contrast to most land tortoises, dependent to varying degrees
protein (though see note on how this changes with age, below). Many aquatic turtles
are predators and most are opportunistic omnivores consuming a wide range of small fish,
snails and similar creatures. Their diet also includes many aquatic plants,
and in some cases, this constitutes the bulk of their food intake.
These provide not only protein but also calcium
in balanced amounts (whole animals are eaten - bones included - not just the
fleshy parts). In captivity, it is essential not to make the all-too-common
mistake of feeding only the `best' meat minus the calcium containing bones.
Large bone splinters can, however, prove to be a danger in their own right if
swallowed whole so many keepers prefer to provide calcium in a safer form
(usually as a proprietary supplement). Good quality supplements of proven
performance include ‘Rep-Cal’ and ‘Miner-All’ with D3 (
Most turtles are actually omnivorous rather than exclusively carnivorous, consuming both animal prey and plant material in the wild. Slider and Painted turtles tend to be far more carnivorous as juveniles, than as adults. It is very easy to overfeed adults on protein-rich meat-based products - do not forget that in the wild adults of these species are predominantly herbivorous!
In all cases, it is certainly not adequate to feed only on commercial turtle flakes which are often of very poor nutritional value and severely lacking in dietary fiber, vitamins and minerals. Nor should oily fish form the staple diet, as these can result in steatitis or fatty infiltration of the liver. Diets containing excessive quantities of fish can also result in induced vitamin-B deficiencies due to the presence in fish of an enzyme called thiaminase, which interferes with the take up of B-group vitamins. It should also be noted that fish oils and fresh meat waste in the water is extremely slow to degrade - it can clog filters and quickly result in bad smelling, poor water quality. The main thing to avoid with diets for any captive turtle is over-reliance upon one single item; this is a very easy mistake to make, but a balanced and varied diet is infinitely superior. Provide as wide a range of the following food items as you possibly can.
Suggested turtle diet
· Plant leaf, aquatic plant and salad material, assorted (freely available)
· Raw (whole) small fish (not frozen, very limited amounts occasionally)**
· Rehydrated low fat dried cat, dog and trout pellets (twice weekly for juveniles - no more than once weekly for adults)
· Zoophobas, crickets and waxworm larvae (limited amounts, occasionally)***
· Earthworms (occasionally)
· Tubifex and bloodworms (excellent for tempting hatchlings to begin feeding)
· Small snails and mollusks (occasionally)**
· Good quality proprietary foods (e.g., Reptomin) three times per week
** Note that these items carry some risk of transmission of certain parasitic organisms such as flukes. For this reason, you may care to exclude them. Turtles can be reared perfectly satisfactorily if these items are omitted.
*** These are particularly useful if confronted by a rescued wild turtle that may not immediately recognize prepared foods as edible.
An average meal can consist of two or three of the above constituents, combined. Rotate ingredients for variety and balance. We have maintained, bred and reared quite literally hundreds of turtles over the past 20 years using this as our general, base-line diet. Where dried food, or floating food sticks, are to be rehydrated, rehydrate using water plus a calcium additive.The technique we have found most effective for achieving this is as follows:
Live prey and salad vegetation should also be dusted in this manner immediately prior to feeding. This is a highly successful way of ensuring that your turtle will obtain all of the essential vitamins and trace elements it requires. On no account rely upon ‘Turtle Flakes’, shrimp, or ‘ant eggs’ as sold in some stores - these products are totally unsuited to the successful rearing of healthy turtles. Most turtles fed on such diets die within a few months from multiple dietary deficiencies.
To avoid contaminating your turtles with Salmonella organisms, it is wise not to feed raw meats, especially chicken or pork - these frequently harbor the organism and if eaten by the turtle the disease will be passed on.
Diets rich in meats are invariably also high in phosphates and low in calcium. This can cause serious problems for turtles, who need high levels of calcium for healthy bone and carapace development. Note that in the wild most aquatic turtles feed regularly upon snails and similar creatures which have a calcium-rich shell. Insect larvae, as taken in considerable numbers by juvenile turtles in the wild, are also comparatively rich in calcium. In captivity, this source is rarely available and therefore additional calcium supplementation is absolutely essential.
Calcium tablets can be successfully hidden in meats, and all foods should heavily dusted with a general high ratio calcium-mineral supplement such as Rep-Cal, Miner-All, etc. Provision of a cuttlefish bone which can be gnawed if required is also recommended. Break it into chunks and float it on the surface of the water -- most turtles love this, and will gain valuable calcium and other trace elements from it.
The ‘Calcium Blocks’ sometimes sold for turtles are not adequate by themselves and should not be relied upon to prevent Metabolic Bone Disease (MBD) - always use a professional grade reptile supplement containing a balanced quantity of food-grade calcium with vitamin D3. In turtles with MBD, the bones of the jaw may be soft and weak and in hatchlings the plastron may remain soft long after it ought to have hardened. Nervous symptoms associated with hypocalcaemia may also be noted (shaking, tremors). These symptoms may appear collectively or individually depending upon the progression and severity of the deficiency. Hatchlings are worse affected (due to their rapid growth and consequent higher calcium demand) but even adults will manifest the condition if placed on an acutely deficient or severely unbalanced diet for long enough.
The underlying bony tissue is porous and thickened and local swellings of the jaw and limbs are commonplace in turtles with MBD. The body, attempting to support the weakened skeleton, surrounds it with a fibrous connective tissue. The parathyroid glands recognize that there is inadequate calcium within the blood-stream, and attempt to rectify the deficiency by leaching calcium from the bones, thus exacerbating the condition. As long as the diet and blood-serum level remain calcium deficient, this vicious cycle continues. Finally death occurs from acute 'calcium collapse'. This condition results directly from inadequate levels of dietary calcium, excessive dietary protein, excessive dietary phosphorous and inadequate levels of vitamin D3. Generally a combination of factors are involved. The condition is 100% preventable and the use of a balanced diet, regular use of quality supplement and provision of UV-B lighting will ensure that it does not affect your turtle.
Most common dietary mistakes by turtle keepers:
Avoid such (often fatal) errors. Research the needs of the species you keep carefully, and use the above diet as your starting point. Ignore contrary advice from pet stores. Pet stores typically give incorrect and misleading advice on turtles.
In addition to provision of an adequate diet, pay careful attention to the general care and maintenance of your turtle. These other articles on our website provide additional vital information on such topics as housing, lighting and water quality:
Further reading on this site:
Mauremys turtles of the Mediterranean - Care and Breeding
(c) A. C. Highfield 1997-2002