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How Big Do Red Eared Slider Turtles Get? [With Pictures]

I bet you own a red-eared slider turtle pet and your worry is how big red-eared slider turtles get to. This is a common question asked by beginner pet owners. They fear that their pet will grow to an extent they will not be adorable anymore. Well, I was also in the same spot before I got myself a red-eared slider turtle pet. I have spent much time learning about the red-eared slider turtle to ensure that I will be able to get him all that he needs. So far, I can say that It has been great since I got him and I want to share some knowledge I have gained about the red-eared slider turtle.

So, how big do red eared slider turtles get? A fully grown red eared slider can grow up to 12 inches in length. These are mostly females. Females are slightly larger than the male. A fully grown make can grow up to 9 inches.


Rarely will you find a red-eared slider turtle grown past that 12 inches size? The size of the red-eared slider turtle is dependent on factors such as the age, the diet, UVB light, and the habitat. Let’s narrow down through these factors and see how they affect the size of the red-eared slider turtle. Also, please check out our post on the best small turtle to keep as a pet.


Most reptiles are known to lay eggs, turtles being reptiles do the same. The size of the turtles’ egg is about 1.5 inches. From there on until the turtle gets to about 3 to 4 years, the growth will rapidly accelerate then drastically reduce past the age of 4 years. During these 4 years, a turtle may have attained a size of about 4 inches. From there onwards, it may take about 2 years to grow another inch. The reason behind this is the diet. Baby turtles like to feed on proteins that aid in their growth. As they grow, their taste gradually changes to love veggies and fruits. It is difficult to tell the age of a turtle just by looking at their size only. Other than the age, diet is the main factor that affects the size of a red-eared slider turtle.

The Diet Of Red Eared Slider Turtles

The foods that the turtles eat play a major role in their growth. This is what makes the difference between a pet turtle and a wild turtle.

Pet turtles get a healthy diet from their owners. The owners will ensure that the turtle gets all the nutrients required. Like I said before, small red-eared turtles enjoy proteins more, and these changes as they grow. The proteins that they feed on include crickets, fish, snails, slugs, earthworms, and boiled eggs.


As they grow, their diet changes to fruits and vegetables. Turtles are attracted to brightly colored fruits such as the carrots, tomatoes, apples, pear, bananas, grapes, and berries. The veggies include corn, beans, beets, carrot tops, lettuce, collard greens, kales, and spinach.


Some supplements also provide the turtles with specific nutrients. You should be careful not to give him more than the required amounts. Too much of everything is poisonous, and even the proteins they love so much is consumed in large quantities will provide the allergies. The supplements include vitamin A and D3 and sometimes calcium. You should only give him supplements if you are unable to provide the foods that contain those nutrients. With these in their diet, the turtle will grow fast and will reach its maximum size more quickly compared to a turtle that struggles to get its food.

Difference Between Male And Female Red Eared Slider Turtles

Females are known to be larger than the males, no doubt. The reason is that she will have to keep the eggs inside her body without breaking them. Their bodies are not as flexible and hence, the more space they have, the higher the chance of the eggs to survive.

UVB Light

Let me say that apart from the diet, UVB light is the other very important requirement in a turtles body. The light is supposed to help with the production of vitamin D3 This vitamin is vital as this is what helps the turtle to absorb the nutrients that he has consumed, such as the calcium. A turtle that lacks UVB light will end having problems with their shell as well as the bones. The light rays also help in their fast growth. To get the UVB rays, the turtle finds a basking area where the UV rays hit them directly and in large amounts. This is the reason why basking is very important for turtles and not only turtles but reptiles in general.

Difference Between Pet And Wild Red Eared Slider Turtles

A pet red-eared slider turtle is very different from a wild one. The differences begin from their size. It is expected that a pet turtle is going to be bigger than a native turtle which is true. A pet turtle has so many privileges that a wild turtle does not. Starting from the aquarium that has a basking area, a feeding area, a pool, and a UVB light bulb. There is any reason why the turtle will not grow to his full potential. For a wild turtle, he will have to search for everything himself starting from the food, the basking area while still being careful not to be hurt by predators. There is also the winter which is also a threat to the wild red-eared turtles. During this time, they will hide until winter is gone. No food, no water, no nothing. They use up the energy stored in their body to survive. How would they grow under such conditions?


How Do I Keep My Turtle Small?

I don’t think it is possible to keep your turtle small. In this case, I would suggest getting a turtle species that remain small even after they are fully grown. A growing turtle will still grow even if you decided not to feed him as it is required. 

How Can I Make My Turtle Grow Faster? 

I think turtles will grow faster if they are in the right conditions. So, for your turtle to grow more quickly, ensure that he has the proper diet, basking area for UVB light and clean water  

Do Turtles Grow To The Size Of Their Tank? 

The size of the tank is not a limitation of your turtles’ growth. If his species do grow, he will grow past the tank size if you had a small tank. Ensure you keep changing the tank.

How Fast Do Red Eared Sliders Grow?

Their fast growth is between the time that he is born up to about four years. By this time, he should be around 3-4 years. After this, his growth rate reduces.

Do Red Eared Slider Turtles Bite?

Turtles are known to be very gentle and peaceful creatures. However, they don’t like to be handled every time, and you should not even try to put your finger near his mouth. They don’t have the clearest of vision.

What is the cost of owning a turtle?

I found out how cheap a red-eared slider turtle is. With just $20, you own yourself one of the common red-eared slider turtles.

This is just an overview of how big do red slider turtles get. You have learned how the conditions help with turtles’ growth and how big they get. You should, therefore, not fear to get a red-eared slider turtle just because of their growth size.

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