'Always destroy a quasi-particle?  (annihilate hole or annihilate particle)
>>> from sympy import Symbol
>>> from sympy.physics.secondquant import Fd
>>> a = Symbol(\'a\', above_fermi=True)
>>> i = Symbol(\'i\', below_fermi=True)
>>> p = Symbol(\'p\')
>>> Fd(a).is_only_q_annihilator
False
>>> Fd(i).is_only_q_annihilator
True
>>> Fd(p).is_only_q_annihilator
False'

@property
def is_only_q_annihilator(self):

    return self.is_only_below_fermi
