If I may concur with my learned colleague and add something to the above in
furtherance ;)
Those species with an alpha or dominant male who "persuedes" the other
males in the tank to show protective female colouration can make sexing the
fish by colour alone difficult. it may sound trite to old-timers but a
trick here is to take the dominant male out and wait until another colours
up, take him out, and so on until no others appear, with the result that
the fishes left in the tank are quite possibly female.
Of course, like Alan says, if you throw all the males together in one tank
of some species then you will only end up with one anyway.
The bottom line is that at least one male and one female are needed to
spawn the fish successfully - it sounds blatently obvious (of Thatcheresque
proportions, actually) but it bears repeating.
Cheers, Andrew
_________________________________________________________________
Andrew Boyd - andrew at pcug.org.au - http://www.tip.net.au/~andrew
Cookie: "Don't worry…Tomorrow's another day."
Sol: "That's what I'm dreading".
ICQ UIN - 11257242