Can you keep a turtle in a 5 gallon tank?

how big is the turtle if its a baby take it back to were ever you got it it might have selaminella( if that's how you spell it )if they wont take it back then try getting a 10 gallon a 5 gallon will work but its to small. what kind of turtle is it? average turtles grow a little more then 12 inches and that's just the shell if its a red eared slider you will need a pond my advice is take it to your local pet store ask a associate if you can leave it there (petco has adoptions) obviously you don't know what your doing so you shouldn't keep it and next time do research before you get a pet