I have also had female swords, or what I was sure were females, that were full adult size change to males. No I have not been young enough to go by the swordlike tail in at least 30 years but this I have observed in fry that I raised to adult size. I do not remember them breeding successfully before or after the change but the anal fin changing into an obvious gonopodium is not so rare that I've never seen it.
Gender Shifting Swordtails
- Thread starter Lansirill
- Start date
Another "magic" story:
Had 7 surviving swordtail fry and put those in 10 gallon. After 2 months took 3 females out to add to the 55 (55 had already a male) and was left with 4 females (very clearly female). Within 2 weeks one of them developed a gonopodium. A month later (all of them are 4 months now) the male started growing the typical sword.
Asked 2 LFS and both said this is a survival thing and is known to happen.
I am very happy about this because now I have two groups of 1 male, 3 female swordtails and they are gorgeous!
L.
Had 7 surviving swordtail fry and put those in 10 gallon. After 2 months took 3 females out to add to the 55 (55 had already a male) and was left with 4 females (very clearly female). Within 2 weeks one of them developed a gonopodium. A month later (all of them are 4 months now) the male started growing the typical sword.
Asked 2 LFS and both said this is a survival thing and is known to happen.
I am very happy about this because now I have two groups of 1 male, 3 female swordtails and they are gorgeous!
L.
I had a 2 yr. old female swordtail that developed a gonopodium and grew a tail. However, I never knew if it had any ability to play its part in breeding as a male. For the younger ones that seemed to change sex, I would have assumed late development. But Maybe 2 yrs. is too late for "late development". I'm not really sure about the topic, just shared my experience.
Too bad, tricksterpup is no longer here. He knew a lot about livebearers.
Too bad, tricksterpup is no longer here. He knew a lot about livebearers.
Swordtail and guppy fry ALL have female appearance until they start sexually maturing. As they grow, their anal fin will become longer and develope into a gonopodium. This isn't a sex change. It's sexual maturation. My swordtails usually take a few months to reach sexual maturity. There is no way to sex the fry before this point.
I read somewhere, long ago (and I certainly don't remember where) that the sex change in swordtails was always female to male (never male to female) and this only takes place occassionaly in old age, when the fish is no longer fertile.
If this really is the case, it's likely due to hormonal changes (or lack of hormones) at old age. Think menopause for fish. Women grow facial hair they didn't have before. I guess fish can grow gonopodiums. I'm glad I'm not a swordtail.
Physiology lesson: In human females, estrogen comes from the ovaries, and the adrenal glands secrete androgenic steroids (androgen hormones) which have a minimal effect on the developement of male characteristics. When women take steroids (for medicinal reasons, such as prednisone) at high doses for an extended period, they will develope some male characteristics (such as facial hair growth) because the adrenals are over stimulated. On the other hand, during menopause when estrogen levels drop, the effects of these hormones become more evident because they are available in a larger proportion to the estrogen which has gone missing.
In males, the steroids have the opposite effect. Forgive me if my terminology isn't exact. It's been 12+ years since I took anatomy/physiology.
Anyhow, I don't know fish anatomy, but I could speculate and say that something similar could very well happen with them.
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I have personaly owned multiple female swordtails that changed genders into males.
Once I had completely full grown four inch pregnant female self abort and grow the sword and gonopodium. I have also witnessed this same swordtail breed successfully.
The experience I remember the best was with my endlers. Had a 3rd generation juvie male with 2 other males and 4 females in a holding tank. I removed the 4 females to take to local lfs - I was breeding for males at the time. Within 2 weeks one of the males had started loosing his fabulous color. Looking closely I realized his gonopodium had shrunk and he was starting to look decidedly female. Since I was trying to breed males I panicked and took 4 females from another tank and introduced them back. Another week passes and the male/female seemed to be regaining his 'maleness,' however, his bright colors never fully restored and he ended up a very pale looking quasi-male - ignored by most of the females. My assumption at the time was he was shifting sex because of the lack of females, but I'm open to the idea it could have been something else...
I have never, however, had a problem with fully-adult males/females changing sex on me. My personal guess on the matter is the fish can tell the sexual population and shift accordingly to make sure there is a balance while young. That, or I'm just off my rocker...which is a good possibility. :grinyes:
I have never, however, had a problem with fully-adult males/females changing sex on me. My personal guess on the matter is the fish can tell the sexual population and shift accordingly to make sure there is a balance while young. That, or I'm just off my rocker...which is a good possibility. :grinyes:
Swordtails do not change sex. Some males just mature at different rates. (late bloomers). The fish that you thought were females were just immature males. It can take some males up to a year or more to mature.
Like I previously stated. I have seen it. Swordtails mature quickly! I am pretty sure that the pregnant female I watched become a male was not a late bloomer.
This has been fascinating to read!!!!I'm serious!
and, it is also slightly entertaining!
kimmisc, I loved this:
"If this really is the case, it's likely due to hormonal changes (or lack of hormones) at old age. Think menopause for fish. Women grow facial hair they didn't have before. I guess fish can grow gonopodiums. I'm glad I'm not a swordtail."
LOL! That is great!
Seriously though, what you said makes sense.
Interesting=
but, glad I'm not a fish!LOL!
Janet
and, it is also slightly entertaining!
kimmisc, I loved this:
"If this really is the case, it's likely due to hormonal changes (or lack of hormones) at old age. Think menopause for fish. Women grow facial hair they didn't have before. I guess fish can grow gonopodiums. I'm glad I'm not a swordtail."
LOL! That is great!
Seriously though, what you said makes sense.
Interesting=
but, glad I'm not a fish!LOL!
Janet
