We used to have a couple. They can just have normal tap water, they need to be able to go in and under the water and also have somewhere to sit out of the water on rocks etc. to keep warm We had a couple of short necks, and we would feed them frozen white fish. We had 2 but I am not sure if they need the "company" or not. You need a fairly big tank - ours were as big as 50c pieces when we got them and bigger than my hand later on. Tank water needs to be kept clean and Ph balanced and you can buy those white thingys that neutralise the water. They were pretty maintenance free but needed regular feeding so if you go away you would need someone to feed them while you are gone. That is all I can think of right now!