Can Crested Geckos Eat Grapes? (Feeding Instructions)

Crested geckos eat fruit and insects in the wild. However, in captivity fruit should only be given in moderation as you can do a lot wrong as a beginner. Crested geckos need a good calcium-to-phosphorus ratio and sadly most fruits have a bad ratio. But what about grapes?

Crested geckos can eat grapes but only as an occasional treat. Grapes have a bad calcium-to-phosphorus ratio but have a low oxalic acid level. Grapes aren’t that popular as a fruit for crested geckos but can be given as a treat.

When you’re new to crested geckos, you want to give a commercial crested gecko diet supplemented with insects. It’s recommended to give fruit, including grapes, only as a treat to your crested gecko. For more experienced users that know what they’re doing fruit can play a more important part in the diet.

In this article, you’ll learn a little bit about the nutritional value of grapes and why they’re mostly suitable as a treat for your crested gecko and not as the foundation of a crested gecko diet. Finally, you’ll learn how to feed them to your crestie.

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Nutritional Value of Grapes

Grapes are fruit and can be used to make different products like wine, jam, jelly, and raisins. A grape can also be eaten fresh and are soft and palatable fruit that is easy to digest.

The following nutritional data comes from FoodData Central:

Total lipid (fat)0.16g
Carbohydrate, by difference18.1g
Fiber, total dietary0.9g
Sugars, total including NLEA15.48g
Calcium, Ca10mg
Iron, Fe0.36mg
Magnesium, Mg7mg
Phosphorus, P20mg
Potassium, K191mg
Sodium, Na2mg
Zinc, Zn0.07mg
Copper, Cu0.127mg
Selenium, Se0.1µg
Vitamin C, total ascorbic acid3.2mg
Vitamin B-60.086mg
Folate, total2µg
Folic acid0µg
Folate, food2µg
Folate, DFE2µg
Choline, total5.6mg
Vitamin B-120µg
Vitamin B-12, added0µg
Vitamin A, RAE3µg
Carotene, beta39µg
Carotene, alpha1µg
Lutein + zeaxanthin72µg
Vitamin E (alpha-tocopherol)0.19mg
Vitamin E, added0mg
Vitamin D (D2 + D3)0µg
Vitamin K (phylloquinone)14.6µg
Fatty acids, total saturated0.054g
Fatty acids, total monounsaturated0.007g
Fatty acids, total polyunsaturated0.048g

Are Grapes Good or Bad for Crested Geckos?

To determine whether grapes are good or bad for crested geckos we need to take a look at two important nutrient levels:

  • the calcium-to-phosphorus ratio (Ca:P ratio)
  • the level of oxalic acid

Ca:P ratio of grapes

Introduction to Ca:P ratio

Crested geckos need calcium to stay healthy and to prevent the development of a specific disease called metabolic bone disease. Gravid females, hatchlings and juveniles have a special need for calcium because they need the calcium to grow and to form eggshells (in the case of gravid females).

Calcium and phosphorus have a special relationship. When the calcium levels raise the phosphate levels are lowered and when the phosphate levels rise, the calcium levels drop. This means that, for crested geckos, foods should contain a lower amount of phosphorus than calcium.

A widely used tool to determine if a food is suitable for crested geckos is the calcium to phosphorus ratio. The Ca:P ratio can be described as a percentage but is more often described in terms of [number]:1 or 1:[number], where 1 is the mineral that’s the lowest of the two. To calculate the calcium to phosphorus ratio this way you’ll need to bring back the lowest number to 1. So, the ratio is calculated by dividing the largest number by the lowest number.

Research has shown that good calcium to phosphorus ratio (Ca:P) is between 1:1 and 2:1. For crested geckos, it’s recommended to have a calcium to phosphorus ratio of 2:1 or better.

Calculating the Ca:P ratio

Calcium10 mg10/10=1
Phosphorus20 mg20/10=2
Ca:P ratio1:2

So, the Ca:P ratio of grapes is 1:2, which is considered a bad ratio. This doesn’t mean that grapes are bad, but you should be aware that they aren’t that beneficial for crested geckos as for example papayas.

Oxalic acid in grapes

Introduction to oxalic acids

Oxalic acid is a compound that’s found naturally in living organisms such as vegetables and fruits. It can be sometimes tasted in food when the amount of oxalic acid is very high. Textbook examples of plants that have a level of high oxalic acid are rhubarbs, star fruit, and spinach.

Oxalic acid is associated with the inhibition of calcium and the formation of kidney stones in humans. Crested geckos also need to avoid eating food that has a high level of oxalic acid. The compound will be bound with minerals such as magnesium and calcium and form oxalates (tiny rectangular crystals).

Since calcium is essential for crested geckos, it’s recommended to stay away from foods that have a medium level of oxalic acid and to avoid foods with a high level of oxalic acid altogether.

Oxalic acid level of grapes

Seedless grapes (both red and green) have a low level of oxalates. You do have to be careful not to give Concord grapes as these contain high levels of oxalates.

Grapes as a treat

A crested gecko diet needs to have a good Ca:P and should be low in oxalic acid. Grapes won’t give your crested gecko the necessary nutrients but can occasionally be given as a treat.

Feeding Grapes to Crested Geckos

How many times to feed grapes?

There are some gecko owners that give their own balanced diet consisting of insects and fruits to their crested geckos. However, there exist enough good commercial diets that offer all the nutrients needed.

If you’re a new crested gecko owner and don’t have experience with balancing the diet of a crested gecko, your crested gecko will benefit the most from a meal replacement powder that has a high nutritional value and add grapes or even better a fruit mash as a treat once or twice a month.

How many grapes can you feed?

If you make a mashed fruit puree you can fill a shallow dish with the same amount as a normal meal replacement powder. If you give fruit as a treat you should give it in small pieces. So only give one or two small seedless grapes.

How to feed grapes to crested geckos?

Crested geckos can’t bite hard so you need to be careful that the food you give can be eaten. Fruits are often mashed in a puree to make them edible. When you feed grapes to your crested gecko you’ll need to do the same. You can slice the grape into very tiny pieces so your crestie can easily eat and digest it.

Want to Learn More?

If you want to learn more about crested geckos as pets, please read the following articles.

If you’re interested in getting crested geckos as pets you should also definitely read our article about baby and juvenile crested gecko care or (adult) crested gecko care.

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