yes, they can and will throw colors that you think they should not. when line breeding this is why they cull. say batch one throws 10 desired fish, and 4 not desired. they cull those 4. then they breed back the new females to the father (the original mother is taken out of the picture). now in theory this female would have 12 of the desired color babies and 2 non desireable. they would cull the 2, and repeat the process. over time the non desireable trait will become less common. it can, and will pop up because the gene is always there. dont make the whole line breeding thing into rocket science (you could , but why), just keep eliminating the ones that dont fit the desired traits as they pop up. nature can boggle the mind. look at squirrels, it takes 2 to breed that have a recessive black gene to produce white offspring. screwy aint it?!🤪