What is an analysis of the theme of "Mirror?"

Certainly a
rather melancholy poem, critic Jo Gill notes that the poem "" is
"catoptric"; that is, it describes while it represents its own structure with two
nine-line stanzas that are balanced and dual in nature. While the mirror reflects
objectivity--the opposite wall that is "pink with speckles"--at the same time, it is
false in its superficial reflection of mere physicality when the woman peers into it as a
measure of herself. And, it is this falseness that is represented by the terrible fish that
arises from the mirror, that unadultered self that does not conform to mere
reflection.

Thus, the theme of Plath's poem arises from the duality of the
mirror. While it reflects a true superficial image, it cannot define a person.  It is the inner
person that one must cultivate on her own, defining oneself by one's own values, not as a
reflection of the values of others.  Herein lies the theme: No mirror can report the soul, the
essence of a person; it can only reflect the visage of a person, a visage which at times may be
false, "a terrible fish."

Now I am a lake.  A
woman bends over me,

Searching my reaches for what she really
is....

I am important to her.

The
person in the mirror searches where she can find no answers, for the soul does not emerge from
the search for self.  It is, however, reflected in the heart. This is surely the
theme.