Friction reducers can be used in fluids for oil and gas operations. Friction reducers can be water-hydratable and can decrease the friction within wellbore components after fully hydrating. The friction reducer can be pre-hydrated at the well site. The friction reducer and water can be combined into a static mixer of a pre-hydration apparatus that forms a mixed fluid. The friction reducer can be retained in the pre-hydration apparatus for a sufficient period of time to allow the friction reducer to hydrate. The mixed fluid containing the pre-hydrated friction reducer can then be added to a base fluid to form a treatment fluid. The treatment fluid can be a fracturing fluid. The pre-hydrated friction reducer can provide an immediate reduction in friction to the treatment fluid as the treatment fluid is being pumped into the wellbore.