Sorry but no... tehy are incredibly predatory and fish and crustaceans form the main part of their diet!!
And you do realise that it will outgrow a 4ft tank dont you?!
They get huge and messy and are nothing short of a nightmare and no one will want to take it off your hands when you no longer want it/can no longer look after it (inevitable, they live a ridiculously long time...) and there are so many in recues and getting euthanized every year because they make such poor pets...
Not terrepin/turtle/slider is suitable for keeping with fish, some people do it but its incredibly cruel and risky, its like locking someone in a room with lion and waiting to see what happens, even if its not hungry enough to kill or eat the person, they are going to be scared out of their wits!
If you want shelly creatures, look at Map or Musk turtles and find a reptile specialist! They are all species that like to sit out of the water (you do need to provide land for all of them!) and bask in the sunlight, this means you will need to provide a hot basking lamp and a UV lamp to replecate that sunlight.
They arent an easy pet. Not very cuddly! Yellow and Red Bellies are more than capable of taking th end of your fingers off and might well do given the chance..... at very least.. i can assure you it hurts like anything!