# sexing guppy fry



## danilykins

So I was looking at the fry, the dozens of fry... and noticed that some are very dark shaded (gray and black) like the females and some are very light colored, I can't see any gray at all. Could it be that they are showing their sex this early ( a week) . Im thinking the dark ones are females and light ones are males. 
*c/p*


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## jrman83

You really won't know for a while, not knowing how old your's are. Some of the females are easy to spot once colors start coming in on their fins and tail, but even then it is not gauranteed. The female colors of yellow tail and black spots is the only color that has been for sure on mine. You have the orange tail and black spots thing, but I just had one I'd thought all along was a female until yesterday. And just this morning I had one that had the grey body and bluish colored tail that I thought was a female and now think it is a male. I still have one that I am not sure of and all of mine are about 2 months old. Gonopodiums take a while to show. Chris may have a different view....all new to me as well.


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## chris oe

The color of the body, or even the fins isn't really a clue, some females color up their fins, and the base body color is generally either golden or gray, and can be mixed even within a drop. The only true tests are the gravid spot and the gonopodium, and the gonopodium is really quite late in developing. Early on if you have very good eyes you will begin to be able to see, at the back of the silvery organ sac, the tiny black spot that is the gravid spot. Some people say they can detect this at birth. I have never been able to do this, of course my eyes aren't sharp. Usually it takes some weeks before I can see it, so I just sort according to which fish I can see it on. Any I detect a spot on go into the female tank, any I can't detect a spot on, I leave. Gradually they grow and mature and you begin to see that there's a characteristic shape, even before the gonopodium develops. The females are much rounder/almost square through the abdomen, where as the males are much longer/almost bullet shaped through that area. Some will be ambiguous for much longer than the others, late in developing color and gonopodium, and those will be your biggest males - early maturers tend to be smaller, although just as colorful, which is odd, because early maturers end up by themselves in the boy's tank (more food, more space) so they ought to get bigger if it were just food and space. I suspect it has something to do with how much the fish are putting into physical growth versus sexual maturation at what stage. I always have to keep an eye on the female tank, because once in awhile I will be wrong about a couple males, usually you can move them before the gono's completely formed, though. It starts getting long and pointed before it forms the tube, and as long as you move them before the tube forms they can't impregnate anybody. but on the whole, the gravid spot gives me an accuracy that's probably in the high nintey percents.


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## jrman83

Yeah, the gravid spot has helped in most of mine and identifying which is which. The last one I am unsure about I can't be 100% sure about. I think it is male. Body is a single dark color...getting darker the older it gets. One of my males is already chasing adult females, not the ones about his size.


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## chris oe

The ones his size don't smell nearly as interesting - lol


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## danilykins

Thanks guys  I will keep an eye on all them to see how this develops


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## jrman83

chris oe said:


> The ones his size don't smell nearly as interesting - lol


Is this how they know? Makes sense as I know they have to figure it out some how. I've also noticed how much they get after females that have just given birth very recently. I've seen the sniffing behavior on fish like Mollies. It is more apparent with them. They do a goosing like dogs do and then further action from there.


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## chris oe

The truth? I don't really know. The research indicates that females like males with orange spots the best, but there hasn't been much research on male preference (that I've found yet). My guess is that females send out pheromones like most other creatures, signaling readiness, and that males zero in on that. Female guppies can store sperm, but will discard stored sperm in favor of fresh sperm if they mate within the seven days after they drop fry, but they tend to hide after they drop, so I'm thinking they must send out some kind of chemical signal saying "come and find me". This is entirely supposition though. 

One of the things I like to do when I have a little spare time is troll the web looking for scientific papers with guppies in the subject, 'cause you find out the most interesting things from those papers.


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## danilykins

> One of the things I like to do when I have a little spare time is troll the web looking for scientific papers with guppies in the subject, 'cause you find out the most interesting things from those papers.


Well at least I know Im not the only one out there that does this lol. My husband thinks Im obsessed.. I say Im learning


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## chris oe

Nah, we're just amateur scientists. Go us!


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## M1ster Stanl3y

a quick glance at the title of this page made me say WTF...

i saw Sexy guppy fry

I was confused, but now i get it.


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