It depends what male you mix the guppy females with, and even then it is unpredictable...
For example:
I've started out with guppy females with pink tails and males with red tails with black dots.
F1 generation ended up with females with pink or yellow tails and males with flame patterned tails (black zig-zag lines with red and orange blots).
F2 generation: mostly female yellow tails and males with again flame patterned tails but with more yellow.
F3 generation: all females with green tails, males with green flame pattern (black zig-zags with green blots) and... surprisingly, two Endler-like guppies with green+red+black bodies but with ugly gray forked tails. I don't know where those two came from. Had nothing like them in tank to be their parents. This generation was sterile.
