The dual symbol of Pisces (one reaching upwards, upstream, towards the light, another downwards into the dark undercurrents of the sea) can signify two different choices of life-path. It can also, I believe, symbolize two states of mind or focuses of interest. In Michel Houellebecq's case, this choice seems rather clear. Through his writing, he has probed the depths of the human psyche in its darkest corners, and caused much commotion by doing so. The fish swimming into the depths cannot escape the neither the suffering nor the perversity of humanity: in fact, it may be drawn to it and even immersed in it. Pisces often comes with a considerable gift of imagination. Together with the literary gifts and verbalization of his Gemini Moon, it enables Houellebecq to relate this pain and depravity to a world that is kept on its toes in apprehension of what might come next.
Houllebecq has been compared to American writer Bret Easton Ellis, a fellow Pisces, for his bleak rendering of modern life in the moral-sexual twilight zone. Not least through the novel Atomized / The Elementary Particles, which won the "International IMPAC Dublin Literary Award". It's an eerie tale of two half-brothers who lead empty, loveless lives but in very different, perhaps polar-opposite ways. A major theme is that of identity and relationships as a merely physical, "particle phenomena", tragically devoid of the illusion of love and warmth.
The Pisces-Gemini combination is defined by a tendency to ruminate on loneliness. It can be obsessed by the idea of being trapped inside a solitary mind, full of vivid, weird fantasies but without a real connection to reality, unable to connect to other people in an authentic emotional sense. It has great potential for empathy and identification with the plights of the fellow man, but the neverending soul-searching and the psychological boundlessness tends to create confusion and irrational anxieties.Houellebecq, or at least the characters portrayed in his writing, seem spot on for this characterization. But perhaps, instead of living it himself, he found an outlet in creativity. Writing as a way to process and analyze difficult questions on life, love and morality.