Eagles Fan

I doubt any have seen the livebearer transformation from male to female. But I am witnessing it right now.

My black sword was a female when I got her Here is how she is changing.
This is all in the anal fin.

1. The fin starts in its normal triangle.
2. The side of the triangle on the side of the tail begins to turn in almost like a hook, with the point still down.
3. The hook gradually folds up pointing in the direction of the tail.*this is where mine is currently*
4 The fin will gradually pull into the male modified anal fin and you have a male livebearer.

Blub

MissMTS

Oh my gosh! The same thing is happening with my swordtail. I was so freaked because I didn't know that they could do that. What causes it?

COBettaCouple

It's the way that livebearers develop gender, caused when they hit a certain age.

MissMTS

Wow. I didn't know that. I have to take him back to the LFS now because I only have 2 females and 2 females with 2 males is a really bad idea. He is about 2.5 inches long so I thought that the sex would already be established because he is twice the size of my other male.

Chief_waterchanger

It is not by any stretch of the imagination common, but there are documented cases where fully functioning females that have dropped fry have turned COMPLETELY to a fully formed and functional male that successfully fertilizes a female.

It is extremely rare, but does happen on occasion.

(Usually it is people misidentifying the gender of a male fish, thinking it is female and it turns out being a slow developer. That is indicative of said fish never dropping fry and then appearing to be male all of a sudden.)

MissMTS

Thanks for the info!

tan.b

just a theory, but i'm sure i read/heard somewhere that in some water systems there is a high level of hormones which can cause fish to change sex. could it be that occurances of this are geographical dependant on where these hormones are leaking into the system?

SereneReyn

never heard this, tho i'd be curious to learn how the hormones get in the water...

tan.b

leakages into reservoirs, bore holes etc perhaps from chemicals sprayed on fields? who knows?! wish i could remember where i'd read/seen it or even better.....had a better memory!!!

deedeehun

I have baby feeder guppies in my tank. They were all females when I put them in the tank. They had the gravid spots and everything! Now one has lost it's gravid spot and the anal fin is becoming more pointed. They are in my 20 gal tank.

Perhaps if there are too many females in the tank, the hormones coming from the fish themselves cause one or more of the fish to change into a male.

I was wondering: Are all fry are born female and then some become male in livebearer species?