Two anionic tetrahedral cages were self-assembled as the only observable products in weakly basic water via imine condensation. The success of the high-yielding formation of the cages in water relies on (i) multivalency enhancing the stability of the imine bond and affording these cages water compatibility and (ii) a guest template with a complementary size and geometry that provides a hydrophobic driving force by occupying the corresponding cage cavity. When all four precursors, namely two trisaldehydes and two trisamines, were combined in water, narcissistic self-sorting occurred when both guest templates were present. In organic media where the hydrophobic effect is absent, narcissistic self-sorting did not occur in the analogous cage systems, confirming the importance of guest templates.