  Rastall gravity is a modified gravity proposal that incorporates a
non-conserved energy momentum tensor (EMT). We study the equivalence between
Rastall gravity and general relativity, analyzing its consequences for an EMT
of dark matter and dark energy. We find that the translation between the
Rastall and Einstein interpretations modifies the equation of state for each
component. For instance, cold dark matter can translate into warm dark matter.
If the EMT components are allowed to interact, the translation also changes the
type of interaction between the components.
