Anyone notice that most guppies end up being female? The only times my guppies have bred, it's been like >75% females. Every time.
So many girls...
- Thread starter captmicha
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Is this surprising to you, or disappointing? Knowing that most keepers encourage keeping 2-3 females per male?
Sex determination in fish is very different than in mammals. In many species of fish, they're born male, and one will become female to breed. Or vice versa--they're born female and the dominant one becomes male. Some can switch as needed if there aren't any of the opposite gender in a community. In some species, they will be difference genders at different stages of their life. It's not just a matter of being XY/XX. For species like guppies where they live in groups and there is strong male aggression, there will always be more females than males that survive, either because adult males kill off the juvenile males before they can become a threat or because the females just produce more females. This can be based on environmental factors or social factors. (IE, lots of males means lots of testosterone, and she's literally swimming in it, as are the fry). In some species, the pH or water temperature will dictate gender.
So...TLDR: yes, that makes sense.
Is this surprising to you, or disappointing? Knowing that most keepers encourage keeping 2-3 females per male?
Sex determination in fish is very different than in mammals. In many species of fish, they're born male, and one will become female to breed. Or vice versa--they're born female and the dominant one becomes male. Some can switch as needed if there aren't any of the opposite gender in a community. In some species, they will be difference genders at different stages of their life. It's not just a matter of being XY/XX. For species like guppies where they live in groups and there is strong male aggression, there will always be more females than males that survive, either because adult males kill off the juvenile males before they can become a threat or because the females just produce more females. This can be based on environmental factors or social factors. (IE, lots of males means lots of testosterone, and she's literally swimming in it, as are the fry). In some species, the pH or water temperature will dictate gender.
So...TLDR: yes, that makes sense.
I notice the same thing too. To get more males in my offspring to develop I like to remove a fish that is becoming male at the first sign and I put them in a separate all male tank. Then another juvenile female will switch over and become male and I just repeat the process. Eventually you can get a lot more males out of the batch but you still end up with a lot of females.
Andy
Andy
There are people who will argue with me and I have no scientific proof to back this up but I will swear to my dying day that there is a correlation and even perhaps causation between water temperature and the sex of live bearers.
Petluvr this would not surprise me a bit, although I have not looked to see if there is any research on the subject. Turtles, alligators and other reptiles definitely have a correlation though between temperature at the egg-deposit site and the gender of offspring, so there is no inherent reason that it couldnt' apply in fish as well.
documentation (ok wiki but stil.
documentation (ok wiki but stil.
interesting in context of the conversation, added support for more females being the norm: http://www.natureworldnews.com/articles/2433/20130613/male-guppies-become-fathers-long-death.htm
do you something i can read on this?..very few fish change sex to my knowledge ..clown fish for one witch sounds like what you are describing.