When Can You Tell Boys And Girls Apart?

[stargirly1208]

i have 8 fry in a 2 gal tank and they must be around a month old and i was just wondering how long does it take to be able to tell who is going to be female and who is going to be male? right now they all appear to be female, but i have heard that they all start off as female so i'm hoping some will change into male! and i also heard that a certain temp can determine the sex of the babies. is any of this true?

 

[Tempestuousfury]

2-3 months should be sufficient for sexing.

It might take time for the gonads to develop, but I would not think that they are all females from birth until they change, since developing ovaries and then replacing them with testes would be quite a waste of energy and protein. *speculation, but I'd say I'm close to right *

Not sure if it is temperature, since I have read mixed info on the issue. The other camp states that it is more a matter of pH. No real clue who is right, though.

 

[GuppyDude]

Yea thats pretty accurate, i was able to sex mine between 2-3 months of age, but the males dont develope the full long colorful tails untill they are about 4 months thogh.

 

[dwarfgourami]

I found I could sex mine much earlier as the females already had a tiny gravid spot which was distinguishable within the first few weeks, so didn't have to wait for the males to develop the gonopodium. Look in the anal region; if there's a tiny black spot, they're not males. With my pink and orange platies the gravid spot never shows much, so there I did have to wait 3 mths for the gonopodium.

 

[fish mad]

I found I could sex mine much earlier as the females already had a tiny gravid spot which was distinguishable within the first few weeks, so didn't have to wait for the males to develop the gonopodium. Look in the anal region; if there's a tiny black spot, they're not males. With my pink and orange platies the gravid spot never shows much, so there I did have to wait 3 mths for the gonopodium.

Ive got one fry at 4 weeks old and its definately a male. Mum was a big old bird though and i couldnt believe the size of her fry. Unfortunately he was the only one to survive.

 

[bettawen]

general concensus is temperature can have an effect on the sex of the fry, the higher the temp more females, the lower more males. keep an eye on the anal fins, they all have them to start but as the males develop the anal fin "fuses" to make the gonopodium

 

[Annastasia]

More evidence supports the pH theroy though. Take a looksee here. If we could get more info on that from people, and possibly temperature too, we might be able to find something out.

As for sexing, as dwarfgourami said, you can usually see little gravid spots on the females. I've had a male with what looked to be a gravid spot at first too, but it turned out it was just his organs (He was light yellow...so pretty much see-through). You can't always go by the gravid, but it's a pretty good indicator. They should start getting gonopodiums by 2-3 months, but you may also have a few late bloomers.

 

[blitztidus]

I still feel the need for more testing, may try it myself. I do belive it may factor in greatly. I normally have fry sexed by 3 months at the latest