Fibonacci sequence implemented in Prolog

gistfile1.prolog

fib(0, 1) :- !.
fib(1, 1) :- !.
fib(N, Result) :- N1 is N - 1, N2 is N - 2, fib(N1, Result1), fib(N2, Result2), Result is Result1 + Result2.

I think
fib(0, 1) :- !.
should be
fib(0, 0) :- !.
because the fibonnaci sequence starts with 0 so, if you think about it, fibonacci at index 0 is 0.
For example:
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
0 | 1 | 1 | 2 | 3 | 5 | 8 | 13 |
Therefore, fibonacci at index 7 is actually 13.

when am I supposed to write simple expressions(non recursive) like "N1 is N - 1"and " Result is Result1 + Result2".on the right of the expression and when should it be on the left

What will be the modification required to print the whole series up to the given index?

fibonacci(0,1):-!. % cut down the backtracking
fibonacci(1,1):-!.

fibonacci(N,X):-
  N > 0, % the constraint to make N always greater than 0; put the integer less than 0 doesn't make sense
  N2 is N - 2, % it doesn't work to pass N-2 into the fibonacci predicate. The "is" is the arithmetic operation, not "=" in other languages 
  N1 is N - 1,
  fibonacci(N2,X2), % get the X2 value
  fibonacci(N1,X1), % get the X1 value
  X is X1 + X2. % calculate the Fibonacci number