  The antideuteron and antihelium-3 production rates at high-energy heavy ion
collisions are calculated in the framework of fusion mechanism. It is supposed,
that anti-p,n,d,^3He participating in the fusion are moving in the mean field
of other fireball constituents. It is demonstrated that at high energies, where
many pions are present in the fireball, the number of produced anti-d and ^3He
is determined by the balance between created and desintegrated (mainly in
collisions with pions) anti-d and ^3He. The explicit formulae for coalescence
parameters are presented and compared with the data.
