Fluid container (1) for arrangement in a beverage container (2), wherein the fluid container (1) extends in an axial direction (3) between a first end (4) and a second end (5) and has a first volume (7) for storing a fluid (8) inside a fluid container wall (6); wherein the fluid container (1) has, between the first end (4) and the second end (5), a central region (9) which has, in the axial direction (3), a constant cross-sectional area (10) which extends transversely to the axial direction (3), and a longitudinal axis (11) which extends parallel to the axial direction (3) and runs through a centroid point of the constant cross-sectional area (10).