How to get more male fry?

[biofish]

Guyssssssss. My guppy fry are all female still. 31 fry were born two weeks ago and so far I only see about 3 (there’s probably more but it’s hard to count when they never stop moving) that don’t have obvious gravid spots already. My tanks are kept at 78°. My female to male fry ratio is about 4:1 but this might just bump it up to 5:1.

I love my ladies, don’t get me wrong, but I would also very much like some boys too

Is there anything I can do to balance this ratio For anyone who can’t remember/hasn’t read my other posts, I’ve always had an uncanny amount of female fry born compared to male despite having many adult female guppies from different stores. Do female fry have a higher change of being given rather than the supposed 50/50 chance? Do they have a higher survival rate?

Helpppppp I have three tanks of just female guppies and only 1 male tank.

@emeraldking Do you know anything?

 

[Back in the fold]

Calling @GaryE ! This is a topic that has concerned breeders of many types of fish. I hope a lot of people chime in on this one. This is a good topic.

 

[biofish]

I was researching it and people seem to believe that higher temperature lead to more male fry? I also read someone thinks a ph of the water also affects the ratio and suggested making the water more basic (making the ph closer to 8. Last time I checked my tanks were at 7.5) for more male fry.

Should I try increasing the temp? Should I try 80°F? 82°F? Or possibly even 84°F?

I don’t wanna use hormones at all to influence it. I just want natural solutions if possible.

 

[emeraldking]

Hi,
Yes, regulating the temperature during the whole pregnancy (so, not just regulate at the end or halfway the pregnancy), "can" influence the sex of the offspring. But I have to put it a bit differently. True, that a higher water temperature will "mostly" result in more male newborns in most ovoviviparous livebearers (with dwarf livebearers like e.g., Neoheterandria elegans and Heterandria formosa it's the other way around). But even when you do put the water temperature higher, once the breeding pairs are used to those higher rates, at some point, the male/female ratio of the offspring will become 50/50,40/60/60/40% again. So, what's the clue? If you change the water temperature significant higher or lower than the water temperature those fish are used to, only then sex manipulations works.

 

[Colin_T]

You can't sex baby guppies until they become sexually mature at around 3 months of age.

 

[I Like Rare Fish]

You can't sex baby guppies until they become sexually mature at around 3 months of age.

This was my thought

However, different temperatures correspond and influence sexes, like in turtles.

 

[GaryE]

Environment works on the triggers that determine gender in fish.

And to me, that's the only general statement worth making. Studies have shown temperature, water chemistry, and a whole range of variables affecting ratios - some that breeders can manipulate. I have a killie species here I can manipulate sex ratios with using water hardness. Why? Dunno, but it has worked for 20 years. Their closest relative didn't respond the same way at all.
I don't think we can even generalize about groups. It's a species by species question, and if you're a breeder, you've probably done the sorts of poorly designed experiments I have. One serious study showed 26 degrees C to be the number for fairly even ratios in Pelvicachromis dwarf cichlids. Beyond that, good luck.

We humans like one size fits all answers, and nature seems to favour head scratching questions.

After years of breeding fish, and trying to influence ratios, I have still lost species to single sex outcomes. One thing to explore is how you raise fry - how small the tank is. They can sex each other before we can see it, and males will often knock each other off pretty effectively in small tanks.

 

[itiwhetu]

It is only natural that a population of guppies will have more females than males. Males then have all the choices under the sun, and the females do the tedious bit of giving birth.

 

[GaryE]

It is only natural that a population of guppies will have more females than males. Males then have all the choices under the sun, and the females do the tedious bit of giving birth.

Except that research shows females do the choosing from among those annoying males. Males will try it with a rock or a snail, and aren't very picky.

That said, males get picked off by predators because of their colours, so more males are probably a good thing.

Many years ago a colleague from Trinidad gave me a jar full of guppies she'd caught in her childhood backyard. I kept them for about 10 years and had pretty even ratios all the way through. I also had a separate tank of wild guppies from coastal Colombia, for 7 years, and they were pretty well the same. If anything, I had more males. But it was remarkable how long it took the wilds to sex out. As I raised batches, I was often unsure if I had any males, til they finally got around to developing.

 

[emeraldking]

It's a species by species question,

True! My reply was based on the majority of ovoviviparous livebearers. My reply does not imply for all kinds of fish.

That said, males get picked off by predators because of their colours, so more males are probably a good thing.

True! Males will become more often victims of predators in comparison to females, because of their colors. That's why guppy populations in waters with a highly predation level, males are less intense colored than guppy males in a low predation area.

Except that research shows females do the choosing from among those annoying males.

No matter how often a male tries to copulate, it's the female that decides if she allows a male to mate with her or not.

You can't sex baby guppies until they become sexually mature at around 3 months of age.

A trained eye can sex guppies already at an early stage. I don't have to wait for three months to sex them. But you're right when it concerns someone who's not that trained.