Why can't you buy guppy females at petland?

[Reefscape]

Hmmmm....interesting...however, this is moving in a slightly different direction now...as before it was stated that guppy fry are a 50/50 ratio....now, its suggested its controlled by temperature? Which would say to me, that under a given tank setup, there is nothing really to say that the fry WILL be 50/50...or at least i dont see anything that says that...and that depending on what temp you run your tank at will determine the sex ratio of the fry?

That quote above is an experiment run on this subject, not what i would class as the norm aquarium in our home for joe bloggs guppy keeper...

Not being argumentative, just trying to learn and understand, based on the facts which are presented....

 

[Hooked Newbie]

I'd have to agree the the guppy expert (GuppyScape) on this one. :lipssealedsmilie:

Everything I've read has stated that while temperature can influence gender in higher animals (turtles, crocdillians, etc.) it has no direct correlation in fish. In their natural habitats, the temps are pretty much stable so there would basically be no mix if gender was controlled by temp.

 

[Reefscape]

I'd have to agree the the guppy expert (GuppyScape) on this one. :lipssealedsmilie:

Everything I've read has stated that while temperature can influence gender in higher animals (turtles, crocdillians, etc.) it has no direct correlation in fish. In their natural habitats, the temps are pretty much stable so there would basically be no mix if gender was controlled by temp.

LOL.....someone actually agreed with me in the FW forum??? WOOOOHOOOOO


Seriously, yes, thats my thoughts entirely....hence why i cannot see, in a normal environment, that a given bunch of fry, say 20, can always be 10 males and 10 females...But, if controlled by temp, it seems possible, going by the documented evidence on the net...which, in reality, i cant dissagree with....but, this always 50/50 sex ratio, under normal circumstances, i have too disagree....untill someone can prove me otherwise...

 

[jpappy789]

The guppy expert speaks!

 

[excuzzzeme]

I my tanks the temps are very stable at 78F. I usually end up with more females than males by a wide margin. Far from a 50/50 mix. More like a 20/80. This has been consistent through several broods. In the peak of summer I had 1 brood that was male dominate. So yes heat does influence sex. I very much disagree that they are unisex when born. I have have maintained many brood over the years and have been able to tell sexual differences quickly. To me, that sounds like an "old wives tale". I would like to see scientific proof to these absurd claims.

It takes one person to make a claim and 20 more will repeat it as fact. Unless the person is of the scientific community, I take it with a grain of salt!.I have my own "proof" that these claims are not valid.

Please understand I am in no way trying to denigrate anyone. Just expressing my opinion.

 

[KarlTh]

Hmmmm....interesting...however, this is moving in a slightly different direction now...as before it was stated that guppy fry are a 50/50 ratio....now, its suggested its controlled by temperature? Which would say to me, that under a given tank setup, there is nothing really to say that the fry WILL be 50/50...or at least i dont see anything that says that...and that depending on what temp you run your tank at will determine the sex ratio of the fry?

That quote above is an experiment run on this subject, not what i would class as the norm aquarium in our home for joe bloggs guppy keeper...

Not being argumentative, just trying to learn and understand, based on the facts which are presented....

I think the facts are that guppies are conceived and born in a 50/50 ratio, but temperature can slightly influence survival rates in the two sexes. The ratios will therefore, in any tank set up, be 50/50 or very close to it; the temperature effect is not very big.

But the 50/50 ratio is an average. A given brood of 20 could be all female or all male. It's just that the more fry you have, the more the ratio will tend towards 50/50. It's like tossing coins. The results are 50/50, but it's perfectly possible to toss 10 heads in a row, but a lot less likely to toss 20.

As to this female domination that some people are recording, I can only say I've never experienced it in any of my tanks. I wonder if some aquarium strains have very weak males, resulting in many deaths at or before birth? Nor is anyone saying they are unisex at birth, simply that they all resemble females, at least to the untrained eye; no flashy colours, and the gonopodium is not yet formed.

I wonder what the ratios are like amongst feeder guppies and endlers? That would be a good lead as to whether selective breeding is producing non-viable male genotypes.

 

[Reefscape]

I suppose this is what i am not seeing anywhere..nowhere can i see that guppy fry are 50/50 sex ratio at birth....hence why i have been looking for info on the net to confirm this, which i cannot find...

Thanks for the discssion on this subject by the way, KarlTh....its interesting...

 

[KarlTh]

The study I linked to did say the normal ratio was 50:50:

The sex ratios of the progenies from survived gravid females were not differed from a balanced sex ratio (P>0.05

Since the vast majority of animals do produce offspring in a 50:50 m:f ratio, it's something it's safe to assume unless there is evidence otherwise. Mine have always been roughly 50:50 and posts on here are the first I've ever heard of people experiencing otherwise.

 

[H3D]

While this whole discussion on genetics seems way off topic, live bearers, including guppies, under normal circumstances tend to have an equal number of male and female offspring. Typically this still slightly favors the female offspring. For instance 11 females and 9 males. For all intensive purposes using a 50/50 ratio is adequate IMO.

I would just like the throw this into the mix as well. Guppies have the ability to change sex. Which makes determining this ratio even harder to do outside of a genetics laboratory.

 

[KarlTh]

To add - I think what I'm saying here is that people may be experiencing skewed ratios but I don't think this is a generic guppy thing; I think it may be related to inbreeding. It's hard to be sure, but I'd say that of guppies I've bought, the females have been a lot hardier than the males.