My swordtail lady is transforming...

[SilentBob]

...Into a swordtail gentleman.

First post about fish and admit I am a complete dunce (fil is the expert but he's away ATM) but whhhhhhhy is my lady transmogrifying?

I have googled and I don't fit into any of the 'categories' that I have found as an explanation for this, quite frankly, terrifying phenomenon

I already have one gentleman swordtail and he and a lady swordtail produced a baby swordtail so I can't see that it could be because of the lack of an alpha male iyswim. Also, the fish in question is fecking huuuuge so not transforming to save her skin.

All other swordtails have died including baby- RIP, Stephen (yes, she was a girl, but also my first Fry )- could this have something to do with it?

It's a little freaky if I'm honest. And I'm not entirely sure I like it!

[TreeSparrow]

Swordtails can't change sex so it's likely you actually have a late developing, sub-dominant male, who is now only developing the tail now that the others have died.