  A dense neutrino medium could experience self-induced flavor conversions on
relatively small scales in the presence of the so-called fast flavor conversion
modes. Owing to the fact that fast conversion scales could be much smaller than
the ones of the traditional collective neutrino oscillations, it has been
speculated that fast modes could lead to some sort of flavor
decoherence/equilibrium. We study the evolution of fast modes in the nonlinear
regime and we show that not only fast modes are not guaranteed to lead to
flavor equilibrium, but also they could lead to some sort of collective
neutrino oscillations but on scales determined by neutrino number density. For
the $\nu_e$ dominated case, we observe large amplitude collective oscillations,
whereas a sort of flavor stabilization is reached for the $\bar{\nu}_e$
dominated case.
