  We consider the top-bottom doublet in the background of the sphaleron for the
realistic case of large non-degeneracy of fermion masses, in particular $m_b=5$
GeV and $m_t=175$ GeV. We propose an axially symmetric $(r,\theta)$-dependent
ansatz for fermion fields and investigate the effects of the non-degeneracy on
them. The exact solution is described, with an error less than 0.01\%, by a set
of ten radial functions. We also propose an approximate solution, in the
$m_b/m_t\rightarrow 0$ limit, with an error ${\cal O}(m_b/m_t)$. We have found
that the effects of non-degeneracy provide a $\theta$-dependence typically
$\sim 10\%$.
