We consider a generalisation of Serre's conjecture for irreducible, conjugate self-dual Galois representations rho : $G_F -> GL_3(\bar F_p)$, where $F$ is an imaginary quadratic field in which $p$ splits. We previously gave a conjecture for the possible Serre weights of rho. If rho is modular and irreducible locally at p we establish this conjecture, modulo weights that are close to the boundary. Under our assumptions there are 9 predicted weights. This is joint work with Matthew Emerton and Toby Gee.