Removed restriction on using fill_value with series

Updated docs

Author: eicchen

doc/source/whatsnew/v3.0.0.rst

@@ -778,6 +778,7 @@ MultiIndex
 - :func:`MultiIndex.get_level_values` accessing a :class:`DatetimeIndex` does not carry the frequency attribute along (:issue:`58327`, :issue:`57949`)
 - Bug in :class:`DataFrame` arithmetic operations in case of unaligned MultiIndex columns (:issue:`60498`)
 - Bug in :class:`DataFrame` arithmetic operations with :class:`Series` in case of unaligned MultiIndex (:issue:`61009`)
+- Bug in :class:`DataFrame` arithmetic operations with :class:`Series` now works with ``fill_value`` parameter (:issue:`61581`)
 - Bug in :meth:`MultiIndex.from_tuples` causing wrong output with input of type tuples having NaN values (:issue:`60695`, :issue:`60988`)
 
 I/O

pandas/core/frame.py

@@ -8382,11 +8382,6 @@ def _flex_arith_method(
         if self._should_reindex_frame_op(other, op, axis, fill_value, level):
             return self._arith_method_with_reindex(other, op)
 
-        if isinstance(other, Series) and fill_value is not None:
-            # TODO: We could allow this in cases where we end up going
-            #  through the DataFrame path
-            raise NotImplementedError(f"fill_value {fill_value} not supported.")
-
         other = ops.maybe_prepare_scalar_for_op(other, self.shape)
         self, other = self._align_for_op(other, axis, flex=True, level=level)