Why is My Water Turtle Not Growing?

Western Painted Turtle

Aquatic turtles are cute and very small when first born, but what most people do not realize at the time is that they can live for up to thirty years and grow quite a lot in that time. Indeed, some aquatic turtles can grow up to sixteen inches in length but are more commonly between 6 and 8 inches at adulthood.

What you need to know though is that not all aquatic turtles grow at the same pace, and even turtles from the same species may not grow at the same rate. We often get questions from concerned aquatic turtle owners about their pets not growing. In most cases, it is simply that the rate of growth is not understood or that their pet is just taking its time reaching the expected growth marker. However, occasionally there are other reasons why water turtlesOpens in a new tab. might have a slow growth rate.

Inadequate Husbandry

Unfortunately, poor husbandry is often the main cause for a slow growth rate in water turtles. These fascinating reptiles require certain conditions that mimic their natural habitat to thrive. Without them, their growth can be affected.


Water turtles require an overall ambient temperature of between 80F and 85F. You will need to heat the waterOpens in a new tab. as well; it should ideally be somewhere between 75F and 80F. Your turtle will also require a basking area where temperatures can be as high as 95F. Remember, water turtles are unable to regulate their own temperature so ensuring that they are warm enough is extremely important. If your turtle gets too cold then it is likely to become less active and may even stop eating, which will then affect growth.

It is essential that you have a working water heater, heat lamp, and a good quality thermometer to ensure you can monitor tank temperatures. You can purchase equipment for your tank set up at a local reptile store or online. Amazon has a great assortment. Click here to seeOpens in a new tab. (opens in a new tab).


In addition to heating, aquatic turtles will need adequate lightingOpens in a new tab.. They need both UVA and UVB lighting, and there are a number of reasons for this. UV lighting is required by water turtles to help with mood regulation, feeding, breeding, and healthy growth. Reptiles such as water turtles require UVB lighting to help them synthesize vitamin D3, which is essential for bone and shell growth. Without vitamin D3, your turtle will be unable to absorb calcium. This could then lead to poor shell growth and a potentially fatal condition known as metabolic bone disease (MBD).


The food you provide can also be a factor in the growth rate of your pet. It is important to feed your aquatic turtle regularlyOpens in a new tab. with suitable food sources. Both meat and plants are required by aquatic turtles. You can offer feeder fish, crickets, or mealworms as well as pieces of raw meat such as chicken and pork. It is important, however, to ensure that any food you provide is chopped into small, bite-size pieces.

Suitable fruits and vegetables include (again, cut into small pieces):

  • kale
  • mustard greens
  • collard greens
  • romaine lettuce
  • squash
  • carrots
  • melons
  • apples.

Turtles can also be fed commercial turtle food, which can be purchased online (here at AmazonOpens in a new tab., if you’re interested) or at a local pet store. In addition to fresh meat, fruit, and vegetables, you should be offering additional vitamins and minerals in the form of calcium and multivitamin supplements. These are typically sold in powdered form and can be sprinkled onto food. Amazon offers these as well ­– click hereOpens in a new tab..

How Big Should a Water Turtle Be?

As mentioned at the beginning of this piece, aquatic turtles typically reach around six to eight inches in length. They will usually be around four inches after their first year, but they do not all reach this size at the same time. For instance, some will reach four inches in around six or seven months and will then not grow any more in that year. Others take the full year to reach this size. This can often be the cause of concern among new or inexperienced owners.

Mississippi Map Turtle
Mississippi Map Turtle

The main thing to remember is that aquatic turtles will grow at their own pace. If your pet seems healthy and is eating well, then it is unlikely that there is a problem.

If you are worried, I suggest taking regular measurements of your turtle and should you become concerned about any other behaviors, or if your pet stops eating, it might be worthwhile contacting your nearest exotic vet for advice.

Photo Credits:


I am a content creator by profession but exotic animals are one of my great passions in life. Over the course of my adulthood, I have had the pleasure of looking after stick insects, terrapins, an Egyptian tortoise, giant African land snails, a crested gecko, a Chilean rose tarantula, a couple of curly-haired tarantulas, and a selection of millipedes, centipedes and worms!

Related Posts