A stable optofluidically tunable fiber laser based on Multimode Interference (MMI) effect is experimentally demonstrated. The tuning mechanism relies on modifying the effective width of the multimode fiber (MMF) using a liquid with a specific refractive index, which in turns tunes the peak wavelength of the filter. We easily demonstrate a tunability of almost 40 nm with a side-mode suppression ratio (SMSR) of 47 dBm, and a 3dB bandwidth of 0.4 nm. The laser was operated at room temperature without any thermal control and the wavelength peak was very stable.