Guppy Fry Situation

Hello! So my Cobra guppy fry have been growing quickly and healthily, and some are beginning to show their colors. Tomorrow it will be a full month since they were born, which is very exciting but also poses a problem. I've heard most guppies become sexually mature at around a month old, and I wouldn't want any inbreeding of course. I do have a spare plastic tank in my closet but I'm not sure how stable it is, and it definitely won't be able to hold around 25 full grown guppies comfortably. What would you all recommend I do? I'd have to divide them by sex. But I am a little confused still. Can guppies become pregnant at such a young age? Should I be worrying about inbreeding yet when they are just a month old? I appreciate any advice or suggestions! - Caroline

 

Essentially, as soon as males are deveoping they can breed and impregnant females, of course females too young won't be able to become pregnant, but generally if the males are developed, females are too, especially because males sometimes develop a bit slow.

If there is an excess of males as well, they will develop slower than the most dominant male, but until they have a gonopodium, they can't do anything.
Luckily, males can be sexed before they have a full gonopodium, around this age the analfin will start to thicken, the more you raise fry and watch them, the easier it will be to tell.

It will start to get a slight white color on the tip of he analfin, it will start to become pointy, at that time you want to remove that fish as it is a male.

Sometimes it can be hard to tell, but if you give us pictures, we can usually tell for you.

I had males who all looked like females being over a month and a half old, this was because I had a male who was dominant and almost done developing colors, his gonopodium was there at a month old, even when he had little colors.
Now, all my 8 'females' are 4 males and 4 females.

The sex of the fry depends on the father, some fathers have more males, others have females, if there is surplus in females, males will develop quicker to up the numbers.

 

Essentially, as soon as males are deveoping they can breed and impregnant females, of course females too young won't be able to become pregnant, but generally if the males are developed, females are too, especially because males sometimes develop a bit slow.

If there is an excess of males as well, they will develop slower than the most dominant male, but until they have a gonopodium, they can't do anything.
Luckily, males can be sexed before they have a full gonopodium, around this age the analfin will start to thicken, the more you raise fry and watch them, the easier it will be to tell.

It will start to get a slight white color on the tip of he analfin, it will start to become pointy, at that time you want to remove that fish as it is a male.

Sometimes it can be hard to tell, but if you give us pictures, we can usually tell for you.

I had males who all looked like females being over a month and a half old, this was because I had a male who was dominant and almost done developing colors, his gonopodium was there at a month old, even when he had little colors.
Now, all my 8 'females' are 4 males and 4 females.

The sex of the fry depends on the father, some fathers have more males, others have females, if there is surplus in females, males will develop quicker to up the numbers.

Thank you so much for explaining! I can understand it a little better now. And that is true, some of the fry I think are females could be males and vice versa. I can generally tell the difference myself, but it is definitely still difficult since they move around so much and are still so small. So do you think I should pull out that plastic tank and separate them before tomorrow? Or should I not worry about it until they form the gonopodium? I appreciate the reply!

 

I think theyll be okay for a bit longer if you don't want to separate them now, and you can pretty much use any tub, like a tupperware or a big bowl even lol

I've been working on buying those small pet carrier tanks so I can separate fish if need be.

Mine haven't really started breeding yet, I thought most of them were pregnant because their bellies got really big over a few days of fasting, but they weren't, because the probably would have dropped their fry by now.
Some of my males even have gonopodiums but still aren't interested in the females.

You can separate them if you'd like, but it's not imperative that you do unless you see males trying to mate/aggression towards other fish.

I've got one developing male who's becoming very aggressive towards the other males, I'm going to have to separate him very soon to ease any stress among the fry.
(I also have to get rid of some males because I plan on breeding and they're all the same color and siblings lol)

It's really up to you and the work you want to do right now.
I sometimes find if I separate fry of any size, one tub ends up slightly neglected compared to the other, even if feeding is the same.
I know not everyone has that issue though.

If you're unsure about some of their sexes, wait a bit before deciding to separate them.
Males who are quick bloomers should be separated sooner so your other males will have a chance at deveoping quickly as well.
Otherwise they could be two months or older and still look like females lol

 

I think theyll be okay for a bit longer if you don't want to separate them now, and you can pretty much use any tub, like a tupperware or a big bowl even lol

I've been working on buying those small pet carrier tanks so I can separate fish if need be.

Mine haven't really started breeding yet, I thought most of them were pregnant because their bellies got really big over a few days of fasting, but they weren't, because the probably would have dropped their fry by now.
Some of my males even have gonopodiums but still aren't interested in the females.

You can separate them if you'd like, but it's not imperative that you do unless you see males trying to mate/aggression towards other fish.

I've got one developing male who's becoming very aggressive towards the other males, I'm going to have to separate him very soon to ease any stress among the fry.
(I also have to get rid of some males because I plan on breeding and they're all the same color and siblings lol)

It's really up to you and the work you want to do right now.
I sometimes find if I separate fry of any size, one tub ends up slightly neglected compared to the other, even if feeding is the same.
I know not everyone has that issue though.

If you're unsure about some of their sexes, wait a bit before deciding to separate them.
Males who are quick bloomers should be separated sooner so your other males will have a chance at deveoping quickly as well.
Otherwise they could be two months or older and still look like females lol

Lol that is true, I didn't think about that. But small pet carrier tanks are a good idea! I think I'll wait a little while longer, I can still barely sex them. Although a couple of them in particular are starting to develop color on their tails, not very much or very bright, but a little color at least.

You've been so helpful, thank you so much! I'll definitely keep your advice in mind, especially once they start getting older.

 

I thought gender was determined by water pH/hardness and temp?

 

I thought gender was determined by water pH/hardness and temp?

When I was talking to Mcasella who raises a heck ton of fry, they mentioned that fry aren't affected by light or temperature, unlike some fish are.

If it was the case of ph, then 7.4-7.6 would produce exactly half and half of each sex every time, as that's what my fry are at, and they weren't developed except one when they met that water.

Their bagged ph was similar.

This is what she said in our conversation:

"The numbers of males and females sadly can't be determined by changing the temperature, so it is all up the the male that fathered them. Sometimes you get more males, sometimes you get more females. I know having a ton of females will cause males to develop sooner if there is a lack of males. Sometimes having dominant males around causes the others to not develop as fast (similar to cuttlefish that smaller males will try and disguise themselves as female to get the chance to breed without beingnoticed, though with fancy guppies maleshave too much color too early for that lol).

Unless they are swimming rapidly females normally keep their analfin flared out from their body.

I have two virgin females of blue moscow type, they are from a green cobra female and a darker blue moscow male. (They haven't been in contact with any males, so will produce fry from the first male they are placed with, helps with breeding when you don't have to "toss" the first drop away as trash (compared to what you are working for) and wait another 4 weeks for results. The cobra female has produced 4 dropsfrom one breeding with the blue moscow male so they should be fairly fertile."

 

Coloration is a heritable trait from the male. Gender, is not.

Male guppies exhibit high levels of phenotypic and genetic variability for several traits such as size, shape and colour, which have been implicated to influence female choice, male mating success and their susceptibility to predation (Reznick & Endler 1982; Houde & Endler 1990; Endler 1995; Brooks & Endler 2001a; Hughes et al. 2005; Lindholm et al. 2005).

 

Coloration is a heritable trait from the male. Gender, is not.

Male's sperm determines sex in livebearers.