YES

TRS:

  fib(0()) -> 0()
  fib(s(0())) -> s(0())
  fib(s(s(x))) -> +(fib(s(x)),fib(x))

max/plus interpretations on N:

  fib_A(x1) = max{5, x1}
  fib#_A(x1) = max{5, x1}
  0_A = 4
  0#_A = 4
  s_A(x1) = max{3, 2 + x1}
  s#_A(x1) = max{3, 2 + x1}
  +_A(x1,x2) = max{5, x1, x2}
  +#_A(x1,x2) = max{5, x1, x2}

precedence:

  0 > fib = s > +