How Big Should a Turtle Tank Be? (Detailed Guide)!

It requires 10 to 15 gallons of water for every inch of the turtle. If you have a 4-inch turtle, it will need a 40-gallon tank. Turtles need to have a large space around their tank as a basking area. It must be big enough for it to walk around without bumping.

Make sure the water level is low enough to accommodate the basking platform. Some turtles like swimming in deep water. You may want to consider getting a taller turtle tank. Other turtles like shallow water but are high enough to soak their bodies. It depends on the turtle species that you will have.

There are different turtle species that you can choose from. Make sure to learn about their needs for their new home. That way, you can ensure that the turtle will survive for a long time. Choose a turtle tank that is big enough to accommodate their needs to make the turtle happy.

Young turtles can survive in a 20-gallon aquarium. But they will eventually grow as long as they are well fed and taken care of. That means that they will need a larger tank by then. It’s better to start with a 40-gallon aquarium so you don’t have to replace it after a short time.

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Turtle Tank Guide for Different Turtles

1. Musk Turtle

Turtle Size: 3 to 4 Inches 

Tank Size: 30 to 40 Gallons

Musk turtle adult size can only reach up to 3 to 4 inches. It can remain small so it’s easier to take care of than other turtle species. This type of turtle can live up to 50 years or even longer. It’s a perfect choice if you want that for a pet.

In the wild, they can be found on ponds or shallow streams, or slow-moving rivers. Musk turtles like staying in the muddy areas of the shallow water. They use it as their shelter and to protect themselves from predators. It lays eggs in the sand that’s close to the shoreline.

2. Painted Turtle

Turtle Size: 7 to 8 Inches

Tank Size: 70 to 80 Gallons

Painted turtles can also remain small during their lifetimes. It’s a perfect pet even for beginners. Their adult size can only teach between 7 to 8 inches. When in captivity, they can live from 15 to 25 years. As long as they are well kept in optimal conditions, they can live for a long time.

These turtles can be found in North America and can survive in every climate. When they are in the wild, they prefer to stay on the margins of rivers and streams. They spend most of their day basking. If you like this title, make sure to provide them enough space for basking.

3. Red Ear Slider Turtle

Turtle Size: 8 to 10 Inches

Tank Size: 80 to 100 Gallons

You can find this type of turtle in almost every pet store. They are easy to care for and a popular choice of pet. The red ear slider turtle size can be between 8 to 10 inches. The females are bigger so you can choose the male if you want a smaller pet.

The red ear slider turtles can be found in the warmer areas. You can find them in the USA, Mexico, and Brazil. They like calm and warm water such as lakes, marshes, and ponds. These turtles are usually soaking in the water and only bask for a short time.

4. Mud Turtle

Turtle Size: 4 to 5 Inches

Tank Size: 40 to 50 Gallons

It’s another turtle species that remain small throughout its lifetime. Their maximum adult size is between 4 to 5 inches. They also have a long lifespan and can reach up to 50 years even in captivity. As long as they are cared for properly, they can reach their maximum lifespan.

Mud turtles prefer to live in ponds that have soft sandy bottoms. As a pet, they need to be in clean water and an oxygenated tank. To stay in great condition, it’s best to use a good filter. They also need a basking platform to get warm and some UV light.

5. Map Turtle

Turtle Size: 6 to 10 Inches

Tank Size: 60 to 100 Gallons

The map turtle may vary from medium to large when it comes to size. The male map turtle can only reach 5 inches in its adult life. While the female can grow between 6 to 10 inches and has a unique look. However, this turtle species is not recommended for beginners.

Map turtles need more care since they are prone to bacterial infections and shell rot. It’s best for more experienced turtle owners. The water quality must always be in top condition. Aquatic plants and a strong filter will help to avoid the need to change the turtle tank water frequently.

6. Box Turtle

Turtle Size: 4 to 8 Inches

Tank Size: 4 sq ft. per Adult

Box turtles have different requirements when it comes to their tank size. These are terrestrial species which means that they stay longer on land. They also have a long lifespan which is between 30 to 40 years if cared for properly. Some even lived up to 100 years or even longer.

It’s more important to find a turtle tank with a big surface area at the bottom. Box turtles spend their lifetime on the ground rather than in water. Occasionally, they soak in water to rehydrate their bodies. Make sure that the water level is low since they can’t swim well.

7. Diamondback Terrapin

Turtle Size: 5 to 7 inches

Tank Size: 50 to 75 gallons

Diamond terrapins can live between 25 to 40 years. They are native to the brackish coastal tidal marshes of the Southern and Northeastern of the US and Bermuda. They can only reach between 5 to 7 inches during their adult life.

The 60 x 30 x 30 cm (24 x 12 x 12 inches) turtle tank will be suitable for a 4 inches terrapin. The more it grows, the bigger the turtle tank should be. That way, the terrapin can reach its full lifespan without any problems.

8. Wood Turtle

Turtle Size: 7 to 8.25 inches

Tank Size: 75 to 100 gallons

Wood turtles have a brownish or gray-brown color. They can live for more than 50 years in the wild or captivity. Their sexual maturity is between 14 to 20 years. These turtles eat a variety of plants and small animals.

They feed on fruits, mushrooms, berries, fish, snails, insects, and more. It’s a perfect pet for beginners since they are easy to care for. Wood turtles are friendly, tame, and easy to handle. They also have endearing personalities.

9. River Cooter Turtle

Turtle Size: 8 to 11 inches

Tank Size: 75 to 100 gallons

The river cooter turtle has a bright green color and light markings when newly hatched. Their markings will darken as they mature. They can be found in rivers and lakes. Although they are sometimes found on springs, ponds, swamps, and water. It includes different aquatic plants and marine flora.

These turtles spend their time mostly on land. They bask and nest in terrestrial environments near the body of water. River cooter turtles females can grow bigger than their male counterparts. So if you want to keep a female, prepare a larger turtle tank for it. They eat meat, shrimp, and insects.

Turtle Tank Tips

  • Don’t Use a Terrarium for Aquatic Turtles

It can easily break from the water pressure. Make sure that it’s an aquarium so it can handle the pressure. An aquarium is thicker since it’s made to house aquatic animals. If you have a box turtle or other terrestrial turtles, you can use a terrarium. They spend most of their time on land so that’s perfect for them.

  • Get a Turtle Tank with At least 10 mm Side Panels

That will be strong enough to stand the water pressure and avoid breaking. The thick side panels will also ensure that your turtle is safe inside. It will ensure that it will not end up outside its tank when you’re not around. It’s very important for aquatic turtles since they live most of their lives in the water.

  • Make Sure the Depth is Greater Than Width

It will allow the turtle to flip over to avoid it drowning when it turns upside down in the water while swimming. Having a deep tank can save your aquatic turtle from those accidents. But if you have a terrestrial turtle, the width matters more than its depth. So, choose a turtle tank depending on the species.

  • Check the Adult Size of the Turtle First

It’s important to know if you get a hatchling or juvenile. This will help you to choose the right turtle tank size. It will provide you with an option to choose a bigger tank size to save you from the need to replace it. This can also avoid them from being uncomfortable as it grows.

  • Plan Before Getting Another Turtle

Choose the tank according to the first one. Add half of the first tank capacity so you can choose the right tank size. Make sure that it can accommodate both turtles. They should be able to move freely and be comfortable to stay healthy.

Frequently Asked Questions

1. Can Turtles Outgrow Their Tanks?

A turtle tank is not the one that will decide the size of a turtle. Although there’s a myth that turtles don’t grow more than their tank. It’s not exactly true since it will depend on what type of turtle you want to put inside that tank. Some turtle species can grow big.

It’s better to learn about their maximum adult size before getting a turtle tank. Their adult size will be determined by their genetics. If the turtle is well fed and taken care of properly, it can grow to its maximum size. You can choose a small type of turtle that doesn’t grow even when they are already mature.

2. What Happens If the Turtle Tank Is in Direct Sunlight?

It’s not a good idea to have the turtle tank in direct sunlight. This can be dangerous for your pet since the water temperature can increase faster. It will have a bad effect on the turtle’s health or can even be lethal. Avoid putting the tank in direct sunlight at all times.

Place the tank where it still can be reached by sunlight but not directly. You can also use aquarium lights if the position of the tank is dark. That’s safer than taking the risk of changing the water temperature. The sunlight can be too strong for your pet.

3. Do Turtle Tanks Need Filters?

Aquariums use filters to maintain the quality of water. It keeps it clean as it circulates so it will be free of waste. Turtles produce more waste than fish so it needs a stronger filter. You need to change the water every day without the filter. If not, the turtle will get sick.

Choose a filter at least two times larger than the turtle tank. It needs a powerful filter to avoid the need to change the water frequently. That’s less effort on you while keeping the turtle healthy. It will be bad for them to swim in dirty water especially if you have an aquatic turtle.

4. Is Lighting Important for Turtle Tanks?

Yes, lighting is essential for the turtle’s survival. They need to have a full spectrum light to synthesize vitamin D3. It’s needed to maintain healthy bones and shell formation for turtles. Exposing the turtle tank to direct sunlight is not a good idea. UVA or UVB lamps should be used.

Turtles need to have the lights on for 10 to 14 hours. They also need 10 to 14 hours of darkness after that. Some aquariums come with a lamp. If your turtle tank doesn’t have one, you can get and install the lighting fixture.

5. Is Heating Needed for Turtle Tanks?

Different turtles need different temperatures to stay comfortable. Heating will help the turtle while it’s basking. You can install a heat lamp in the basking area for these moments. It’s best for terrestrial turtles but also needed by aquatic species.

Install the heating during the colder months to make the turtle comfortable. Musk and mud turtles spend their lives mostly on water. But these species also need their basking platforms. They will be basking at one point so they also need to have a heating lamp.

Turtle Tank Essentials

1. Basking Platform

Turtle tanks need to have a basking platform. Cooter, maps, sliders, and painted turtles spend a lot of time basking. Aquatic turtles need to bask at least once daily. When the turtle goes on basking, it helps them to regulate their body temperature.

Basking also allows them to dry off to avoid infections. It also helps them to stay warm. Add a UVB lamp on the basking area so they can also get their needed UVB rays from there. It will help the turtle to stay healthy to reach its full lifespan.

2. Substrate

It’s optional since substrates make cleaning the turtle tank difficult. Food bits can get stuck and it will make the tank unsanitary. Although it can house live plants on the turtle tank.

The turtle can hide on them and it will make it look more aesthetic. It’s not advisable to use this because it’s hard to clean. You can find other types of bedding if you must have one.

3. Pebbles

Pebbles can create a clean and pleasing look for your turtle tank. It’s good bedding for the aquarium. They also come in different colors and shapes. It will make your turtle tank look more attractive.

If you decide to use pebbles, make sure to use the big ones. That way, the turtles will not try to eat it that can cause harm. Avoid adding small pebbles. You sort them out first before putting them on the tank.

4. Flourite Gravel

The flourite gravel is a porous clay that’s good for aquatic plants. Just make sure to go for the large fluorite. It’s better if ingestion of this will be avoided. Turtles will find it less appealing if it’s bigger.

It applies to everything that you are planning to add to the tank. If it’s too small, the turtle may swallow it. So it’s better to check them first for small pieces. If it’s too small and can fit in the turtle’s mouth, don’t add it to the tank anymore.

5. Sand

Sand is another bedding that you can use for your turtle tank. Although it’s difficult to clean, it remains to be a popular choice. Turtles enjoy sand since they dig on it which makes it worth the effort.

If you must use it, avoid adding too much sand to the tank. It will make it harder to clean if it’s too thick. You can also just add it to one area of the tank. Just have enough for the turtle to enjoy it.

6. Accessories

Plants and rocks can be used as turtle tank accessories. It can provide a natural appearance and add some hiding spots for the turtle. This can serve as your turtle’s playground or hiding place. It will make the turtle feel more comfortable.

7. Decorations

Decorations such as plants are not essential for survival. The turtle can still live a healthy life without them. But it provides a nice look for the turtle tank. You can use logs, caves, and smooth rocks. It will serve as the turtle’s hiding place. Avoid putting too many decorations.

Things to Remember When Choosing Turtle Tank Accessories

  • Check first if the plants that you will add to the turtle tank are non-toxic.

Turtles will attempt to eat them and it can be dangerous. Check the decorations and accessories for sharp edges. It can injure the turtle so you have to avoid it from happening.

  • All the rocks and accessories that you get from nature should be sterilized.

Boil water and place the accessories. It will kill germs that will potentially contaminate the turtle tank. Once it’s done, you can add them for the turtle to play with.

  • Avoid putting enclosure types of decorations underwater.

Turtles can get stuck on them if you do this. They can’t swim well like the fish underwater. It can end up in a disaster so place them in the dry area instead. That way, it will avoid your turtle from drowning.

  • Make sure that the decorations are more than an inch.

It will avoid getting swallowed by the turtle. This can be bad for their health if they end up eating small accessories. Remember, they don’t know what’s good or bad for them. It’s your responsibility to avoid accidents.


Now that you have a better idea of how big a turtle tank should be, you can get started. Taking care of a turtle begins with preparing the tank and its environment. It will stay there for a long time so make sure the turtle is always comfortable. It’s essential to ensure that the turtle tank is also clean all the time. That will keep your turtle healthy and make it possible to live longer. Start designing a turtle tank now and make your pet happier.

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