Water Cleanliness

Water quality is the most important factor for maintaining the health of a diamondback terrapins. This is even more important if they are kept in fresh water. 

Diamondback terrapins are one of the most difficult North American turtles to work with. Their water needs to be kept very clean or they will develop skin problems. Normally the first sign that the water isn’t maintained properly is their eyes will develop a red ring around them or they develop white patches on their skin. This is extremely bad for them and cause death within a couple of days if left untreated. 

The truth is they do require much cleaner water than most other aquatic turtles. Diamondback terrapins are not the best turtle for people that have never worked with turtles before. However with proper filtering and care they can thrive in captivity.

Water Temperatures

Water temperature varies for the size of the diamondback terrapin. For hatchlings the water temperature should be around 85F. This helps them in developing at a good rate. Juveniles can be housed around 82F. For adults anywhere between 76F and 80F. 

In ponds the water temperature wouldn’t be regulated and will range a lot more depending on the time of year.

Lighting and Basking Areas

Lighting is very important for all turtles in general. Basking areas need to be provided in every tank and they should be easily accessible for the turtles. This platforms must allow them to get completely dried out, including their plastron. UVA and UVB rays are necessary for proper bone growth and maintenance. Without UVB rays their body can’t process vitamin D which can led to bone disease. Proper basking areas that allow them to dry out their carapace and plastron helps prevent shell rot and other shell problems. Basking is also used to raise their body temperature. Good basking will aid in shedding off old loose scutes.

For turtles housed indoors mercury vapor bulbs can be used to provide UVA and UVB rays as well as a heat source. Mega-Ray 100 watt bulbs is a great option and last about 18 months. Be sure the keep the bulb around 8 inches above the surface of the basking area. The basking area temperature should be around 90F.

The UVA/UVB output of the bulb will decrease over time. A solar meter should be used ever month to verify the UV index is preforming properly. Solarmeter Model 6.5R can be used the test the output of the bulb.

In small and medium size tanks floating platforms can be used for basking area. Do not use rocks for basking platforms, they can be very dangerous. If the pile of rocks shifts it can trap a turtle. Adults tend to rush into the water whenever someone approaches they can hit the rocks causing them to chip their shells. Lastly a more practical reason rocks take up more room in the aquarium than a floating platform. Leaving less space for them to swim.

In larger setups wooden ramps should be used for basking platforms.

Just like most things real sun is the best. Taking diamondback terrapins outside once a week for an 30 minutes to an hour of real sunlight can be very beneficial. Make sure it is not too warm, hatchlings and even adults can get cooked if the sun or basking area if it is too warm.


Overall substrate is not recommended in tanks for turtles. The tanks stay cleaner without a place for food and waste to get trapped in. If substrate is really desired the only kind recommend for diamondback terrapins is crushed coral. It is a much better than using gravel.

Gravel can get impacted in their digestive system while a small size Florida crushed coral (1/8” to 1/4”) likely won’t. Crushed coral can be found at most saltwater fish stores. 

Crushed coral is also a great source of calcium and it will wear down their beaks as well. In the wild, adult females can be seen grazing on coral and crushed shells, especially in the spring before they become gravid. 

Tank Size

Bigger is always better, an adult pair of diamondback terrapins need at least a 70 gallon aquarium.  Medium and large Waterland Tubs are great for housing multiple diamondback terrains and for breeding setup. Plus with Waterland Tubs there is no need to build an additional nesting area, as the tubs are designed with on. Another option is an 150 gallon Rubbermaid stock tanks. An 150 gallon tank can comfortably house 4 females and 3 males. 

Stock tanks are great for breeding because they are normally deeper than aquariums.  Most adult diamondback terrapins need the water depth to be at a minimum of 12 inches before they will mate. 

Separate Feeding Container 

Feeding diamondback terrapins separate from their habitat will help keep the tank much cleaner. Diamondback terrapins are notoriously messiest eaters. They use their large jaws to crush their food instead of biting it. It is highly recommend to feed them separately and this is even more important if they are being fed seafood.

Brackish Vs Fresh Water Debate

To use brackish or fresh water is a subject of great debate among the diamondback terrapin community. As mentioned earlier diamondback terrapins are very susceptible to shell rot and skin issues. If they are housed in fresh water their chances of developing shell rot and skin problems are greater than if they are housed in brackish water (1.012 to 1.018). The only really drawback to housing them in brackish water is they will need to have access to fresh water once a week. This can be simply achieved by placing them in container with fresh water. They will drink for several minutes. After 15 minutes they can be returned to the brackish water. 

There are several different situations that can impact the need for brackish water. 

Captive born hatchlings can generally be raised in fresh water without any problems. It is always important to keep a close watch for shell rot and skin problems. If their water becomes even a little bit dirty they will develop skin problems and possibly shell rot.

Captive born adult diamondback terrapins that have been raised in fresh water can also be kept in fresh water.

Wild caught adult diamondback terrapins should be kept in brackish water (1.012 to 1.014) for the entirety of their lives. If they are kept in fresh water they will almost undoubtedly develop shell rot. Also if they are were recently removed from the wild they should be housed at a higher saline level (1.017 to 1.019) for the first three months and then the level can be lowered to 1.012 to 1.014.

Wild caught juvenile diamondback terrapins can in most cases be converted to fresh water (though it is preferable to keep them in brackish water). Converting them to fresh water will take time. Start them out at a higher saline level (1.017 to 1.019) for a couple of months and then start lowering the level by .002 every two weeks until the level is down to 1.008 and then they can be switch over to fresh water. Keep a very close eye out for shell rot as they will be more susceptible to developing it as the level of salt drops.

Wild caught hatchling diamondback terrapins can typically be housed in fresh water from the beginning. They can normally survive their entire life in fresh water without any problems.

Some breeders have third, fourth and even fifth generation captive born diamondback terrapins housed in fresh water for decades without problems. Most experienced diamondback terrapin keepers are able to keep captive born diamondback terrapins in fresh water. However a lot of beginners and even some experienced diamondback terrapin hobbyist that have problems with keeping them in fresh water. This is why there is such debated over the issue. Filtration, water cleanliness and basking area can also play large factors in the overall health.  

In the wild adult diamondback terrapins are not found living in fresh water. There are several locations where diamondbacks can be found in strictly salt water, miles from any brackish or fresh water. This leads a lot of people to believe that they are better off in brackish water.