  We prove that a discrete subgroup generated by two lattices in opposite
minimal horospherical subgroups of $SL(3,\mathbb{C})$ is arithmetic and thus by
a Borel and Harish-Chandra also a lattice. We follow the method and ideas used
by Oh in \cite{Ref13}. There, Oh proves the same result for lattices in minimal
horospherical subgroups of $SL(n,\mathbb{R})$. The method consists of studying
the orbits of the generating lattices in the horospherical subgroups under the
conjugation action of the commutator of the corresponding Levi subgroup in
order to obtain a rational structure for $SL(3,\mathbb{C})$. A theorem of
Ratner reduces the possibilities for the closure of the orbits. Then, by the
discreteness of the generated subgroup, it can be shown the closeness of the
orbits. Finally, using this information, it's possible to find a rational form
such that the subgroup generated by the lattices is arithmetic.
