sex change?

[ketyana]

I have been keeping fish now for years, I have only one tank and therefore know the small range of fish I have very well

My favourite is the black phantom tetra, I know this fish!!
and therefore asking this question is fairly embarassing but....

I have a schoal of 7 black phantoms, I have had them about a year give or take a death being replaced the most recent cant have been in there less than 5-6 months, for those that dont know the species they are easy to sex, the males are silver and black with a scithe shape dorsal fin, the females have a rounder fin, a redish coloring, and red pelvic fins, they are very distinctive sex wise there are 2 males and 5 females...........or rather there WERE 2 males and 5 females

I can Identify my original males (I know my fish and my tank well) but there is a third, or close to a third, one of my females is changing!!!! Infact rather rapidly

I dont expect anyone to believe this, but I know it to be true, his/her dorsal is now much more male shaped, she is almost male in form and her fins are a very dark colour but the red at the tips still marking her as the changing female, her size is similar to the males and to be honest soon I dont think that she will retain any of these female markings. I have added nothing to the tank other than food and clean water, no chemicals treatments etc

Trust me, I picked these fish I know them and I chose them as clearly male or female, this is a new change there was no way she/he was anything other than a clearly female fish when she entered the tank!!!

Please if anyone can shed light on this, or has any comment please answer

 

[Teelie]

Several species of fish can change sex, usually only when there is a lack of the opposite sex but I've never heard of tetras doing it or in that kind of situation. Still, doesn't really surprise me to hear it's happening.

 

[ketyana]

I have had mentioned to me that some chilids have been know to change sex if there is a lack of male (or turn female if there is a lack of those)

I have heard of some marine reef fish that can

But a tetra in a situation of 5 to 2, that has to be a one off!!!

 

[sylvia]

I don't think tetras can change sex. It may be a slow-maturing male. Swordtails can change sex though the results have never yet been proven fertile... I've heard of other fish changing as well but in all the black phantom tetras I have kept, I have never seen this (I love black phantoms BTW - my favourite tetra!).

 

[ketyana]

An immature male would not have started with the red female colouring though
If it was an immature female I could understand it not having developed the red finnage when young, but female to male this theory would not work IMO

 

[Bignose]

I think Sylvia is onto the right track about slowly developing. Remember, the colorations and indicators are only species averages, we don't think much about a more-brightly-than-usual colored fish, but a duller than usual fish can present a mystery. Ultimately, they are all individuals, and each develops and shows uniquely. Besides, we all remember the "Pat" character from Saturday Night Live, right?