Here are a couple of links I found on fish morphing
http://www.aquariumsite.org/families.cfm
"Wrasses come in a multitude of shapes, colours and sizes, from the small cleaner wrasse and lunar-tailed wrasse, to the large broomtail wrasse, which, as its name implies, has a large brush-like tail with ragged, split ends. These colorful fishes inhabit all reef environments. They feed mainly on small invertebrates, either on the bottom or in midwater. They usually spawn a dusk either in pairs or in-groups that are dominated by one or more gaudily colored males. The numerous tiny eggs a rise to the surface and are not cared for by the parents. Most wrasses are capable of female to male sex change."
http://www.wetwebmedia.com/FWSubWebIndex/poecillidfaqs.htm
"Livebearer sex change
I placed five grown females into a community tank,
> and a month later have four females and a male? Do
> they morph if no males are available?
> <Hee hee... females, males of what?
swordtails
<Actually, yes.... this and other livebearing toothed carps (poeciliids) can/do change their sex in events of disproportionality, need. Bob Fenner> "
