One way to tell how a sign will cope with Mercury retrograde is to consider its symbol, McGuirk says. For example, Sagittarius, represented by the Archer or the Centaur, is heavily associated with forward movement. Mercury appears to be moving backward when it enters retrograde, so this sign may struggle with the sensation of delayed — or even reversed — movement. By that same token, a sign like Pisces, which is symbolised by the Fish, may have an easier time, since fish can swim in all directions, McGuirk explains.