Habitat
Most terrapins, are mostly aquatic, they like to have lots of swimming space with something they can climb onto to get out of the water. The dry area should have a UVB reptile light shining onto it and a heat lamp as turtles love to bask, alternatively a mercury vapour bulb which offers heat and UV in one bulb.
Substrate
Although gravel and sand is very popular for fish tanks these generally are unsuitable for terrapins. Small gravel can be accidentally eaten by your pets and become impacted. Sand can destroy filters and age them prematurely, however with some species such as soft shell terrapins, sand is required. Terrapins are very messy and so I keep the bottom of my tank clear with no stones or bricks to make water changes easier, however if you can handle the water changes with gravel in then go ahead and make it look interesting, the turtles will love digging in it. You could use bigger stones but you must be careful how you place things in the tank, terrapins are clumsy and you don’t want to come home to find your precious turtle trapped under a stone.
Plants
They like to have things to climb on and swim through, I found some great plastic plants at my local reptile shop which are attached to the glass by suction pads. These are brilliant because while the turtles are light they can climb to the top of them and sit out of the water. You can use live plants, they may eat them, but that’s fine, I know there are a couple of plants which are poisonous to them so maybe use the same kind as the shop use where you got your terrapin just to be safe. To see a list of poisonous plants, click here. To see a list of recommended natural foods, click here.
Basking site
Most terrapin stores sell ‘Turtle docks.’ This is an artificial rock which floats on the water, it has suction pads to hold it in place and can adjust to the water level, it even has an access ramp for them. You could use rocks to create your own original basking site but again, please make sure everything is stable or they will knock them over. Its important that the basking site has a UVB light and a heat lamp above it so the turtles are encouraged to come out and sunbathe. Try not to take away too much water space with the construction of your basking site, the more swimming space the better.
Water Quality
This is one of the most important care points for your terrapins as poor water quality can lead to many different illness as well as unpleasant smells in the house. Filters are rated based on fish, but turtles create more waste, so generally most terrapin keepers use external filters which are rated to 2-3x the amount of water in the tank. Ideally you are aiming for 40L of water (not just tank size) per inch of shell length of the biggest turtle, plus 20L per inch of shell length for each additional turtle. A 10-20% water change per week is recommended but this is dependant on water quality and it is advisable to have a water test kit so you can moniter the levels to make sure the water is safe. When cleaning flter media, never use tap water, this will kill any good bacteria which has built up and will start your tanks cycle from the beginning. Once the tank has cycled and the levels are OK, you should be able to do water changes less frequently
To find out how much water your terrapin(s) require, click here.
Temperature
Keep a thermometer on the tank and don’t forget to check the temperature daily if possible. The best way to keep the water at a warmer temperature for hatchlings or some species is an aquarium heater, they cost about £15. However, these heaters are made of glass and are not suitable for use with snapping turtles who could make a meal of one of these.
You can either get a plastic guard for them, or you can get titanium heaters. However, I find that my tank tends to stay just above 20°C without any heating, it all depends where the tank is kept and the species you are keeping. The best kind of thermometer to moniter the temperature are the digital ones, make sure you buy one for use in water though, sticky strips which go on the outside the tank are another method, they are cheap and unbreakable, but often inaccurate. The final method is with liquid thermometers but I would not personally recommend leaving these in the tank for long periods of time incase they are broken.
To find out your terrapin's temperature requirements, check out the caresheets or the forum.
Ventilation
Ventilation is a very important part of your terrapins habitat. A lack of ventilation can cause serious shell problems. Most keepers don't use lids at all, however, you must be very considerate when using perfume, deodorant, air freshner, polish, etc. You must also be aware of the fact that if the basking site is too high with no lid on the tank you are practically inviting the terrapins out of their tank. If you do have an open set up remember to consider other pets in the house, such as dogs or cats and how easy it is for them to get access to your terrapins.
Lighting
Please see individual caresheets or the forum for species specific advice.
Thanks to Graham Knight and Neil Bidle for some useful information