Abstract: A rotary fluid agitator is provided. The rotary fluid agitator essentially comprises a fluid conduit that is positioned vertically within a storage tank holding a quantity of fluid, such as a drilling fluid. At least one nozzle is attached to the fluid conduit for jetting a stream of fluid into to the fluid contained within the tank. A drive means is connected to the fluid conduit and rotates the conduit to sweep the nozzle through a 360-degree arcuate path at a predetermined rotational frequency. A fluid pump is attached in fluid communication with the interior volume of the tank and pumps a quantity of drilling fluid through a fluid circulation line and through the fluid conduit to be jetted out of the nozzle. As the nozzle is swept through the arcuate path a conically shaped fluid flow path is created in the fluid contained within the tank causing the jetted fluid to tangentially act upon the fluid thereby keeping all solid particulates mixed with the fluid in suspension.