  This article investigates the qualitative aspects of dark solitons of
one-dimensional Gross-Pitaevskii equations with general nonlocal interactions,
which correspond to traveling waves with subsonic speeds. Under general
conditions on the potential interaction term, we provide uniform bounds,
demonstrate the existence of symmetric solitons, and identify conditions under
which monotonicity is lost. Additionally, we present new properties of black
solitons. Moreover, we establish the nonlocal-to-local convergence, i.e. the
convergence of the soliton of the nonlocal model toward the explicit dark
solitons of the local Gross-Pitaevskii equation.
