  In this study we consider an exponential decaying form for dark energy as EoS
parameter in order to discuss the dynamics of the universe. Firstly, assuming
that universe is filled with an ideal fluid which consists of exponential
decaying dark energy we obtain time dependent behavior of several physical
quantities such as energy density, pressure and others for dark energy, dark
energy-matter coupling and non-coupling cases. Secondly, using scalar field
instead of an ideal fluid we obtain these physical quantities in terms of
scalar potential and kinetic term for the same cases in scalar-tensor
formalism. Finally we show that ideal fluid and scalar-tensor description of
dark energy give mathematically equivalent results for this EoS parameter.
