  In this Letter we study the effect of Pauli blocking on the Efimov states in
a quantum Fermi gas and illustrate that the universal Efimov potential is
altered at large distances. We obtain the universal spectrum flow of Efimov
trimers when the Fermi density is varied and further consider the effect of
scattering of trimers by the Fermi sea. We argue that the universal flow is
robust against fluctuating particle-hole pairs that result in an infrared
catastrophe in impurity problems.
