Embodiments relate to fluid baffles and parts and kits for making such baffles. For example, some embodiments relate to a fluid baffle for use in a tank, where the baffle comprises: a body defining an interior volume and defining a plurality of fluid passage apertures at spaced positions around the body to allow fluid to easily pass into and out of the interior volume; wherein the body comprises a continuous wall that defines a plurality of convex regions spaced from each other around the body and defines concave regions between the convex regions.