hozzie

Why do swordtails change gender?

I have had a male and 2 females for a year. The male is very...errr.... ardent? rampant? He displays to any fish in the tank and is a sucessful father.

One of the females has developed male gonopodium and is beginning to grow a 'sword'. Its happened over the past month or so, prob longer but i only noticed then. 'She' is also beginning to slim down from being a big female and is now sleeker than her sister.

Why does this happen? I could understand it if there was an absence of males. Will she become a fully functioning boy?

Very strange.

Helene

aquarist48

Hello Hozzie. I've never heard of Sword Tails changing sexes. That doesn't mean it isn't so. Maybe the one you thought was a female was just a late bloomer? I'll be looking forward to seeing the responses you receive.
Have a great weekend!
Ken

hozzie

LOL. At one point you could see fry eyes; so I am fairly sure she was female.....

I like the concept of late blooming..... means theres still hope for ME :P

H

aquarist48

LOL. So the fish in question has given birth?
Ken

hozzie

she last had babies that i noticed around 5/6 months ago... now i think about it, she hasnt looked pregnant for a while now. she is a pineapple sword, so the white belly shows babies easily. None there now, no little black gravid triangle at all...

Just got magnifying glass out, thats definitely a MALE 'bit' she's grown.

But WHY? thats what really fascinates me.

eiginh

I'm not sure why but that does seem really fascinating. The Swordtail doesn't have to pay for it either...

gremlin

I have heard of this happening before. A friend of mine who has had swordtails for quite a while told me her older females will sometimes grow a sword and "become" males. She keeps all of her swords and so some of hers are several years old. I googled swordtails to see if I could find documentation - I found a site that says that this does happen occasionally with older females although they are generally infertile. Here is the link

http://animal-world.com/encyclo/fres...swordtails.php

iloveengl

Wow who would've thought? Fascinating, though!

aquarist48

Oh cool! This is a first for me. Thanks Gremlin! I appreciate the link
Ken

hozzie

Glad I am not going mad. Will find a camera and take some pics, will be interesting to have a record of her 'change'. The sword is growing quite fast on her tail. So far she isnt interested in the other female and my resident male has lost all interest in 'her'.

She's not elderly really, around a year old at most, and shows no signs of parasites... so I still wonder exactly why she's changed.

Lol eiginh, if people could do it wouldnt the world be an even more interesting place.

Thanks for the link.

helene

hozzie

Finally found a camera. She/he has developed really quickly but I still wonder what exactly triggers the change?

Attached Images

	swordtail change.jpg (48.9 KB, 129 views)
	Change sex 3.jpg (51.4 KB, 127 views)

eiginh

IDK I still think it's cool lol

bolivianbaby

I agree with Pete. That's cool!

redlessi

All I can say is WOW!!!!

hozzie

The transformation seems complete.

The Sex change sword is now courting the female. Its a wonderfully diverse world we live in lol.

He is now exhibiting all male characteristics, chasing the female, displaying his sword and arguing with the existing male.

the only difference between him and the other male is the size. he has stayed the same size as the female, not smaller and slimmer like males usually are.

My poor girl has lost a sister and gained another pest!

EdnJean

Hi All,

What are the odds? I came onto the forum today to tell of exactly the same story...sort of.

I bought 2 female swordtails, to bring up number of females in the tank. One was all white (snowy) and the other white with a red/orange head, lookinglike a coi, so we named her coi.
After a couple months, I noticed coi beginning to grow a sword. Now coi has a huge sword, bigger than him! He is still large like a female, much larger than the other male in the tank, and does try to mate with Snowy.
Ed

hozzie

Hi Ed

I have read quite scholarly articles saying this doesnt happen unless there are no males in the tank, then a female will change to fill the gap. That wasnt the case for you or for me it seems. Other articles say it is a total myth.

My original male is quite put out, he doesnt seem to know what to do with this enormous male who has gradually appeared in his tank.

I wonder if they can ever be fertile though, it seems unlikely but then it would seem a waste of time if so.

She/he is very pretty though.

Helene

hooedc

Wow thats crazy

Gouramiguy17

I think I have read in a couple places that all swords are born female, then some change to make an even ratio. It is also like clownfish, all are born male then the alpha male turns into a female. There is also another fish that changes gender but I can't think of it right now

gremlin

Kind of reminds me of Jurassic Park - Life will find a way...

summer

we had 4 females and bought a m/f pair as I wanted baby fish (awww) so we had 5 females and a beautiful and prolific male. the new female arrived already pregnant so that was a good start. the original 4 were all from the same batch at the LFS and quite big and fat (you could tell they were girls). so we named the male Joey and the girls rachel, monica etc (you get the picture?)

so the female had her babies and we rescued 4 and put them in a breeder tank. about a week later I noticed one of our females was growing a tail fin. soon she had a full tail and gonad thingy

then the male (who previously treated her like a girl, chased her; herded her etc) started to chase her away from the others, quite aggressively too, then stopped her/him from feeding. after a day or so of this we managed to find the male/female a new home. she/he still remained fat like the other girls.

I didn't notice he/she chase the girls for mating, and as we only had him/her a few months and the male a few days, I don't know if she/he has had babies in the past.

sorry it's a long post but this fascinates me

wonton55912

ummmmm they cant change gender

gremlin

Yes, they can and they do. Swordtails are not the only fish in the world that do so. Google " can fish change gender " and you will find several websites with info.

wonton55912

oh. can platies do that also?

gremlin

Swordtails are the only commonly kept tropical fish that I have heard of doing this - however, anything is possible...

wonton55912

just wondering...

Randog

The absence of external male characteristics doesn't a female make.

One must take a closer look.

At about 6 weeks old, all swords can be sexed if you have microscope.

Females have 2 opening in front of their anal fin. The one towards the front is their butt and the one behind is their breeding opening. Males have only one, this is their butt.

Their are one average with swordtails, 4 differnet points in their growth when a male matures.

The first stage, at 6 weeks, is one that confounds and frustrates serious breeders. Sometimes one of the males will mature while alarmly small. I try to seperate all my males from the females at this point. Otherwise the little rascal in question begins his unauthorized mayham. These sneaky guys often have the characteristics I am trying to eliminate.

The other stages vary but commonly the late bloomers are the best. They promote good size and proof of good health in their offspring.

As far as sex changes go. For the most part it never literally takes place. Ussually it happens to be a late blooming male in a tank with many females and the unattentive own losses track of who has gaven birth.

It also seems to take place when a strain with hormone problems has those traits too tightly bred into them. This causes a menopausial female to take on the male characteristics but not literally be a male. This does happen to take place in some humans. Look at my aunt Marie for instance. These visually apparent males are sterile when it comes to their newly developed body parts.

In cases of true sex changes, strick seperation of female from males must be abhered to, in order to varify. Their sex must be proven while young and then have their presence in your tanks strickly tracted. All breeding must be done artificially (google it). Their matings and broods must be recorded maticlessly. Only when a authentic female has given birth and then truely turned male and proven to be male by producing a brood through artificial insemination, can it be truely proven.

Otherwise you just have the equivalent of the bearded lady.

hozzie

Thank you for your reply.

all i can say is that the shemale in question showed definite signs of fry inside her, she was pale coloured and the gravid grey triangle was obvious to the point of eyes being visible. this is a community tank in which no fry have ever survived. There were 2 females and 1 male in the tank so no abundance of females to trigger late development. I find it hard to believe that the fish I had for many months as a fully functioning female was in fact a male.

the fish looks female in size, the body is the same size as the other female with large abdomen as opposed to the slimline shape of the male. she/he is twice as big in mass as either of my 2 (one in another tank) males. the male genitalia and sword is unmistakable now and shehe behaves in a male fashion but less aggressively sexually than the original male.

tis interesting but i do think she changed sex.

Helene

hyun007

It is crazy, can you imagine if that happened to your girl/wife

chumzhujun

i think if a there only females. A female will sacrifice itself and be a male