Abstract: The present disclosure provides fixer fluid compositions and related systems and methods. In one example, a fixer fluid can comprise a liquid vehicle, a surfactant, and a cationic polymer. The liquid vehicle can include water and co-solvent having a boiling point from 160° C. to 250° C., the co-solvent present in the fixer fluid in an amount of 1 wt % to 40 wt %. The surfactant can be present in the fixer fluid in an amount of 0.1 wt % to 10 wt %. The cationic polymer can be present in the fixer fluid in an amount of 0.1 wt % to 25 wt %. The fixer fluid can be formulated for printing on non-porous media and does not include more than 5 wt % volatile co-solvent and more than 3 wt % non-volatile co-solvent.