How Fast Can Red-Eared Sliders Grow?


If you have a red-eared slider or you want to get one, you are going to need to know how fast they can grow and eventually how big they could become.

Red-eared sliders do their fastest growth in their first year. They can grow as fast as 3 inches in their first year and about an inch a year after that. They can grow to be about 8-10 inches for males and 10-12 inches for females. Usually they will have reached their maximum size when they are between 5-7 years old, though this can vary.

When you pick a red-eared slider for your turtle companion, it is important to remember you’re picking one of the largest pond turtles that there are. You need to make sure you have the right size tank and other equipment so that you can properly care for your red-eared slider and give it the best life you possibly can.

There are many factors that affect the growth rate of young red-eared sliders. Diet, environment, and genetics will all be major contributing factors to your turtles growth rate. If you feed them a properly balanced diet with a tank that is ten gallons for every inch of shell, then this will give your turtle the best chance it has of reaching its full genetic potential.

It is important to plan in advance. A fully matured 10 inch red-eared slider would thrive the best in a 100 gallon tank! A good compromise might be to get a larger tank that will serve you well the first few years, so you will not have to be constantly upgrading your tank.

Not all red-eared sliders grow at the same rate, nor do they grow to the same size. Even if you feed them a premium diet with the best tank and basking equipment they may simply be a smaller turtle because of their genetics. Just like with people we must do our best, but ultimately we should accept and love our turtle even if it doesn’t end up in the end at the size we would want.

Diet and Red-Eared Slider Growth

Diet plays an extremely significant part in a red-eared sliders growth rate and their size at full maturity. They will need the necessary amount of protein and calcium and as much healthy dark green vegetables as they will eat.

Protein is key when it comes to growth in all animals with red-eared slider being no exception. Muscles, tissue, and important bodily function depend upon protein for their efficient cellular mechanisms. The best sources of protein for a young red-eared slider come in the form of commercial turtles pellets. These will provide a young red-eared slider with a balanced nutritious diet.

While protein is very important to help a red-eared slider grow it is not the only dietary factor. Red-eared slider, while being more carnivorous when they’re young, are also omnivores. This means they eat both meat and vegetables, requiring both to provide them with maximum health and allow them to be able to reach their full growth potential.

So supplement your turtles protein with some dark leafy greens. This will provide variety to a turtles diet while also helping to make sure that they get all the vitamin and nutrients to fuel their healthy growth.

Some veggies that are good to feed your red-eared slider:

Red-eared sliders enjoy a wide variety of greens are a great addition to their diet to give them nutrients and variety.
  • Collard greens
  • Kale
  • spinach
  • peas
  • dandelion greens
  • squash
  • water lettuce
  • red-leaf lettuce

All of these vegetables would be excellent food to supplement your turtles diet with. Try to avoid feeding them iceberg lettuce and celery as they contain mainly water and very little vital nutrients, there really just filler.

Along with protein and vegetables there’s a third factor that makes a big difference as well. That would be the big C, calcium. A turtles bones and shell depends greatly upon calcium. It is literally the building block of a turtle’s personal home, their shell. Without enough calcium a young red-eared slider wont be able to grow at the proper speed and to its full potential. In fact without enough calcium a turtle can get very sick, possibly sick enough to die.

Cuttlebone is a great source of calcium for turtles. It can be purchased commercially or you can prepare it yourself with a few steps.

One good way to give your red-eared slider enough calcium is to throw into their tank a block of cuttlebone. Cuttlebone is a white chalky substance that you can give turtles to peck and munch on to give them some more calcium. Just make sure to cut off the hard backing as this part of the cuttlebone can potentially choke a young turtle.

Another way of provding calcium is to throw in a calcium vitamin supplement. These can be bought at a commercial pet store and you put them in the water where they dissolve. Then over time the turtle can absorb the dissolved calcium through their skin as they swim in the water.

If you make sure that your red-eared slider has a full diet of protein, dark leafy greens and calcium should ensure that when it comes to their diet you are doing what you can to give your little guy their full growth and health.

Genetics and a Red-Eared Sliders Growth Limitations

Ultimately while you as your turtles keeper can influence their growth through providing a balanced diet as well as good access to basking and UVB light. Some of your red-eared sliders growth will be determined by a factor that you can not control, their genetics.

How big and how fast a red-eared slider can grow is partially determined by the limits of their species and who their parents were. While you should do your best to provide them with the basic necessities of growth like diet, and a proper basking area and tank. You should not try to force greater growth then that. In the past some people have had the idea that by force feeding their turtle they could perhaps grow super turtles.

This is false, while you can by providing good nourishment and environmental conditions for your turtle ensure they reach their genetic pontential any more than that will just hurt them and cause them to suffer from obesity and shell pyramiding.

Often red-eared sliders will do a great deal of growth in their first year of life. Growing as much as 3 to even 4 inches in that first year if given all the need nourishment. After that you could expect roughly an inch a year of growth until they meet their genetic maximum usually some where between the ages 5 and 8 or so.

How Big Red-Eared Sliders Can Become and What Size Tank You Need

Red-eared sliders are very large aquatic turtles. In fact their one of the biggest fo the different types of pond turtles. You can expect a male red-eared slider to grow as big as 8-10 inches and the females even large at about 10-12 inches. So if your thinking of getting a red-eared slider make sure that you have the funds and equipment to be able to accommodate their eventual size.

They start out really small like little cute turtle gum drops but as they grow older their going to get much much bigger than that. So you need to provide them with the right size tank for the size of your turtle.

A general rule of thumb sometimes adoringly called the rule of shell. Is about ten gallons of tank size for every inch that a turtles shell is long.

So this would mean that a red-eared slider about 2 inches long in shell length should have a tank that is at least 20 gallons big. If 4 inches of shell length then the tank should be at least 40 gallons. So when a red-eared slider reaches its full size somewhere between 8-12 inches then depending upon their exact size your going to need a tank that is somewhere between 80 gallons up to 120 gallons.

Those are some very large tank sizes, thus why it is so important to make sure that your going to be able to accommodate that size of tank for your red-eared slider when the time comes. If the tank ends up being too small for a turtle then that will make the turtle more susceptible to diseases, the water will be harder to clean and your turtle will just be very unhappy.

So keep in mind your red-eared sliders eventual full size and make the appropriate preparations for it.

How to Measure Your Red-Eared Slider

When people talk about the size of a turtle they are usually referring the the straight inch length of turtles shell. This would be straight across the shell as if it was flat, you don’t count the distance of the shells curve, just it’s straight length. This part of a turtles shell is usually called the plastron.

Here is a handy method that you can use to measure your red-eared slider and their shell growth over time. Make sure to be very gentle whenever you are handling your turtle.

  • Place your turtle upside down on its back. They wont like this and will probably get upset. It should be okay your only going to keep them like this long enough to measure.
  • Get a good measuring tape and start your measurement from the end of the turtles shell.
  • Measure the distance from the shells beginning near the turtles tail up to where it ends near the head.
  • Then note the distance on a handy chart or in a note book. If you do this monthly or maybe at least yearly then you will be able to construct a nifty chart of your turtles growth out of the data.

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