How big do red eared slider turtles get?

A Red-eared slider is one of the most sought-after species of turtles that are taken in as pets. They are also commonly known as the Slider Turtle, Water Slider Turtle, or plainly the Red Eared Slider Turtle. It is a favorite pet turtle species in the United States and is highly sought after in other parts of the world as well. Owing to its popularity and density, it is the most commonly traded turtle in the world.

Thinking about getting a pet turtle home? Here is everything you need to know about taking care of them: How to take care of a turtle

How big do red eared slider turtles get

The Red-Eared Slider is native to the southern part of the States and a few parts of Mexico. One very interesting thing to note about the red-eared slider is that it is an invasive organism. An invasive species is known to outgrow and take over the existing indigenous species of a given habitat. Because of this invasive nature of the red-eared slider, its extent is a lot of other regions apart from the one it is a native of. It is interesting to note that in a report published by the International Union for Conservation of Nature, the red-eared slider was included in the list of the world’s 100 most invasive species.

How big do Red-Eared Sliders get in captivity?

The Red-Eared Slider is an aquatic turtle but unlike most pet aquatic turtles, it tends to grow quite big in size. It is found that the slider turtle can grow the size of a Frisbee, on a good day. The taxonomic name of a Red-Eared Slider is trachemys scripta elegans. Like most other pets and general animal species, their growth and size are dependent on their living conditions. Since they are pets, the space that is given to them in the tank and the environment that is maintained for them become very instrumental in determining the rate of growth of the Red-Eared Slider.

The lifespan of the Red-Eared Slider is twenty to thirty years and it goes through a lot of growth and changes in the first quarter of its lifespan. They show the maximum growth rate in the first five years of their life. The first five years hence are influenced heavily by their existing living conditions and physiological setup. After five years, their growth rate decreases marginally up until they are seven years old. For those two years, their growth rate slows down but remains steady. By the time the Red-Eared slider is seven years old, it reaches its maximum size.

Given the best care and the most favorable conditions to live in, the Red-Eared Slider can live up to thirty years of age and can reach the size of 12 inches and sometimes more. After they reach their biggest size and have reached the age seven, their needs in terms of space, diet and environment changes based on their growth.

What Factors Affect How Big They Get?

It may sound very generic and repetitive but the emphasis that is being laid on the importance of well-balanced nutrition for the red-eared slider cannot get shortchanged by any other factors. The food it eats, the place it lives in, and the activity it does matter the most. Having said that, these are a couple more factors apart from their food intake that is said to determine how big the red-eared slider gets.

The factors can be broadly divided into three.


The Red-Eared Slider is an enthusiastic eater. By nature, they are omnivores feeding on various plants and insects and smaller fish primarily to meet their protein nutritional requirement. In the wild, they feed on aquatic invertebrates, small frogs, and newts. In captivity, however, it is a challenge to maintain the same nature of diet for them and so a combination diet of vegetables, feeder fish, insects, and small amphibians is offered to them.

A major part of their diet is supposed to consist of vegetables , especially the dark green variety like kale, mustard greens, collard greens, carrot tops, and swiss chard. Vitamin A-rich vegetables like carrots and bell peppers also are liked by them.

When we talk about live prey and meat-based feed for the slider turtle, the easiest option for the pet owner is to give them worms, krills, crickets, and dried shrimp. They are all great sources of protein. It also needs to be noted that feeding live fish to the turtle will provide it with the mental and physical stimulation to keep its hunting instinct awake.

A lot of protein intake in the form of a non-vegetarian diet is essential in the early years of the turtle’s life. Its growth rate depends heavily on the type of food they are given. That is why until the age of five, the red-eared turtle requires a high protein diet. Their feed should also be rich in calories and full of calcium and Vitamin A primarily. As they grow, the nature of their diet shifts from protein-based to a more sustainable plant-based diet. As far as fruits are concerned, they must not be added to the slider turtle’s diet as they cause diarrhea in them. Similarly, spinach should be avoided as well.

Leafy greens that can float on the surface of the water are a great feed option for the turtle as they can keep munching on them all throughout the day while swimming around and fulfilling their nutritional requirements. Keeping the turtle’s diet as varied and dynamic as possible will provide it with complete nourishment and remove the possibility of nutritional deficiencies.


This cannot be stressed enough but if you give the red-eared slider more space to swim around, the chances of it living a longer life and growing bigger are more. Since the slider turtle is an aquatic turtle, it needs to swim around a lot. While we take care of its diet, trying to mimic its natural eating habits, it is also important to make sure that the slider’s environment is also mimicked to the most extent possible. For the red-eared turtle to reach its full growth potential and develop fully keeping its social temperament intact, the tank should be big and spacious.

A baby red-eared slider needs to be housed in a tank that is 30 gallons or more. It can spend the first year of its life in this tank before moving into a bigger tank, preferably a 55 gallon capacity tank. In the juvenile stage, the turtle can spend its time in the 55-gallon tank but as it inches towards the full grown stage, it will need a much bigger tank to thrive in. That is the reason why it is necessary to upgrade the tank to a 125-gallon capacity tank so that the adult slider turtle has ample space to move about.

Apart from having big tanks to house them, it is also necessary to make sure that these tanks are also well maintained and kept clean at all times. Red-eared sliders are messy turtles by nature. They leave their droppings and the debris of their food lying on the bed of the tank. Cleaning the tank regularly and leaving the debris with a net is important every single day. Bigger tanks also help ease the work of a water filtration system which is mandatory in a tank that houses the slider turtle. Apart from keeping the tank clean, maintaining the optimum water temperature, salinity, pH and chemical balance is also a very important contributor to the growth of the red-eared slider.

Keeping the water clean in the aquarium also prevents turtles from getting infections. Turtles are constantly at the risk of being exposed to Salmonella and so hygiene is of utmost importance.


The Gender of the slider turtle helps a great deal in determining its size and how big it would get. The female and the male sliders do not show any different characteristics till they reach the adult stage. The rate of growth is not very different for them till they reach sexual maturity.  As soon as they present sexual dimorphism, they start to show different attributes of growth. It is interesting

Read our guide If you are wondering how to know if your turtle is dead or undergoing Brumation.

How fast do red-eared slider turtles grow?

The Red-Eared Slider grows the most in the first five years of its life. Based on the rate of growth and its social abilities, the lifetime of the slider turtle can be classified into three stages.

Red Eared Slider Growth Chart:

Lifestage of the Red-eared SliderAgeSize (diameter)
Baby Stage3 months1 inch
Juvenile1-4 years4.5-5 inches
Adult5 years +8-12 inches
Red Eared Slider Growth Chart

How Big Are Baby Red-Eared Sliders?

Red-eared sliders as babies are a crowd favorite. They are adorable and friendly, their temperament is also very positive. As a baby, the red-eared slider turtle grows up to over one inch in size. They are considered as babies for the first three months of their life in which they weigh less than 60 grams and are literally as big as a coin. Their fascinatingly small size and adaptability make them cuddly pets.

How Big Are Juvenile Red-Eared Sliders?

Red-eared slider turtles that fall between the age of three months to the age of four years come under the category of Juveniles. Although they are in the stage where their growth rate shoots up considerably, they are still quite tiny when compared to their full adult selves. At the age of four years, they tend to be around 4.5 to 5 inches long. From the age of one, their growth age stays steady at a healthy 1.5 inches per year.

How Big Are Adult Red-Eared Sliders?

Red-eared slider turtles attain sexual maturity at the age of five and that is when they are considered to have attained adult status. Although they have now moved on to the adult zone, they will not have reached their full length. By the time they turn five, a red-eared slider will have reached around 10-12 inches in length. This measurement stands true for the female of this species whereas the male sliders are comparatively smaller in size and measure somewhere between 8-10 inches. 

The growth rate in the adult red-eared slider is much slower when compared to the baby and juvenile sliders. As far as the weight is concerned, the male slider is smaller in size and weight than the female slider. A fully mature female weighs up to 500 grams and the male slider will weigh around 300 grams.  

When Are Red-Eared Sliders Fully Grown?

A Red-eared slider is considered to have attained fully grown-up status at the age of 8. This is the age when the slider turtles reach the maximum size and weight in their lifetime. 


How big is a 1-year-old red-eared slider?

A red-eared slider weighs around 100 grams and attains a length of 2.5 inches.

How can you tell the age of a turtle?

There is no definite way of telling the exact age of the turtle but one can take a guess based on certain markers. The number of rings on the turtle’s belly is supposed to give an idea of its age. The size and color of its exoskeleton also help in guessing the age.


Under appropriate living conditions and optimal care, a Red-eared slider can grow up to 12 inches in its lifetime. They grow up to 3 inches in the first year of their life and maintain a good growth rate till they attain full growth till 8 years of age. The main factors that contribute to its healthy growth are healthy nutrition, proper habitat care, and to some extent, its personal genetic makeup. As long as you provide your slider turtle with a large tank and a diet that is nourishing, it will thrive and grow in good health.

Now that you have made up your mind to get a Red-eared slider turtle home, you will be glad to know that they thrive in captivity. Read all about it here: How long do red eared slider turtles live in captivity.

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