  We prove the decay in the energy space for the solution to the defocusing
biharmonic Hartree-Fock equations with mass-supercritical and
energy-subcritical Choquard-type nonlinearity in space dimension $d\geq3$. We
treat both the free and the perturbed by a potential case. As a direct
consequence, we obtain large-data scattering in $H^2(\mathbb R^d)^N, \, N\geq
1$.
