Guppy Phenomenon

a young male guppy not fully developed it can easy be mistaken as a female

http/www.nytimes.com/1984/12/04/science/sex-change-in-fish-found-common.html

http/www.bio.davidson.edu/Courses/anphys/1999/Rice/Rice.htm

http/www.coralscience.org/main/articles/development-5/fish-sex-change

http/www.jstor.org/pss/1310421

http/www.physorg.com/news63990518.html

http/128.197.153.21/msoren/Molloy.pdf


It doesn't seem out of this world to me. Nature will find a way. I'm not saying without a doubt that TOS's guppy has achieved this but that it's certainly possible isn't it?

Interesting reading,All we need now is the same in depth studies and reports on Poeciliid fishes where the male sex organs are outside the body in the form of the gonapodium
I still think the physiological changes required for sex changes in Poeciliid fish would be too much to achieve

I agree its all about the dominance IMO, i had a group of 8 swordtails, 2 developed males and 6 'females' 1 of these females then became male, and still to this day despite now being the only male has no sword as the remaining 2 females are more dominate than him

I've kept and bred many livebearers over the years and have never experienced this

An interesting list of references you have there Caprichoso. Unfortunately the guppy, Poecilia reticulata, is not a reef fish or a cichlid. There are many fish among those groups that do indeed exhibit sex reversals based on environmental factors but the case of guppies sex is determined by genetics instead. Since genes do not vary with time, the true sex of guppies also does not change.

OldMan47 said:

An interesting list of references you have there Caprichoso. Unfortunately the guppy, Poecilia reticulata, is not a reef fish or a cichlid. There are many fish among those groups that do indeed exhibit sex reversals based on environmental factors but the case of guppies sex is determined by genetics instead. Since genes do not vary with time, the true sex of guppies also does not change.

Click to expand...

But, there can be genetic anomalies that can occur, can there not? I just think when you consider the strange and seemingly impossible feats that can occur in nature, that anything is possible. Science is constantly being revised and we are forced to change our minds about things that we once thought were impossible. I'm not disagreeing with you, I'm just letting my mind float around the possibility that the things we have thought to be true, may not always be set in stone. Anyway, I sound like a fringe dweller, so I'll shut up now lol.

There can be strange looking fish that exhibit a sex that they do not actually possess. By using things like hormone treatments during development, all dwarf gouramis offered by pet shops for sale in the US resemble males. That is not the result of simply sorting fish before shipping them.

Manipulation of sex characteristics being expressed can easily be done in many animals. I thought the discussion was around true sex changes. That actually happens in many cichlid species and may well also happen among some reef fish as the referenced articles would state. In those fish, fully functional adult fish will undergo a sex change when the population is a single sex and they will become fully functional members of the other sex. I have seen no evidence in real life or the literature of that happening in poeciliids or Xiphophorus.

If one fish can do it, another species might is like saying that if one mammal can do something, another might. Bats can fly but I never expect to see a person fly without a machine of some sort, even if it only a kite.

Yeah but it's not just "one" fish that can sex change and I don't know if comparing bats to people is a comparable statement lol, although I do understand what you're getting at. The only way to know would be to have their DNA tested before and after which is kind of a moot point in this case. And you are correct, there doesn't appear to be any literature on this happening in poeciliids or xiphophorus....yet...