Swordtail Sex Change?

Question
Hi there. I have heard quite a lot of information on swordtails saying that they change from female to male on occasion. I just have a few questions (more than a few, really):

First off, what are the signs that a female is going to change?
How long does the process usually take?
Are there behavior differences during (not after) the process?
Under what conditions/scenarios would a female become male (i.e. if a male died, if there are no males present, random)?
Which female turns male (the most dominant, or is it unpredictable)?
Are the newly formed males fertile?
Are the newly formed males more intense in coloration?

Thanks for all the information!

Answer
You know she is going to change when she starts growing a tail extension.

That is completely variable

SHe'll start acting male

Only if there are no males

THe most dominant

Yes, or there would be no purpose to the whole excercise

Not usually