How Big Do Pet Turtles Grow?

Red ear sliders are a breed of aquatic turtle, meaning they spend most of their time in the water. Native to the South, he's named for the red stripe just behind his eyes. He’ll have black spots on his tummy too. Full grown, he’ll get up 11 inches, making him a tad bit larger than the cute little guy swimming in the tank at the pet store. In order to keep him comfy, you’ll need at least a 90-gallon tank, but he’ll love as big of a tank as you can get him. A good rule of thumb is to have 10 gallons of tank per each inch your turtle’s shell is long.

Box turtles are smaller than sliders, growing to only about 5 or 6 inches in length. Box turtles aren’t aquatic, and actually aren’t very good at swimming at all. Just because he’s smaller, doesn’t mean he can live in a tiny, indoor terrarium. An outdoor home is best. Keeping him in a pen in the country where he has some rotting leaves or moist dirt will keep a box turtle happy. Just be aware they live 30 to 50 years, so he’s a long-term commitment.

Painted turtles are aquatic turtles like sliders. They don’t grow as large though, usually reaching between 5 and 7 inches in size. Male painted turtles are smaller than females. He’s called a painted turtle because the bottom side of his shell is bright orange. While he can be kept in a large indoor aquarium, at least 50 gallons, he’ll be happiest in an outdoor pond. Make sure the area is fenced in so he doesn’t fall victim to predators.

Map turtles are aquatic, so he’ll need a large tank or outdoor pond with a place he can climb out and bask. Male map turtles only grow to 5 or 6 inches, while females can grow up to 7 inches long. If you want to keep multiple map turtles, make sure they have plenty of room to have space of their own, and beware that females are more aggressive and territorial than males. Map turtles are sensitive to poor water conditions, so he’ll need a filtered tank with a bubbler to keep him healthy.