Sexing Fry?

[Vampyrechic]

What age can you sex fry? I have 17 swordtail fry, born about two weeks ago. I also have a guppy fry born about three weeks ago. What age can I sex them? I figured around 3-4 months, but just wanted to check. I read online that the male guppy fry had a more pointed anal fin and the female fry has a rounded anal fin. I looked at my guppy and its pointed, so its a male? Thanks for the help.

 

[Andy Sager]

Sexing fry

What age can you sex fry? I have 17 swordtail fry, born about two weeks ago. I also have a guppy fry born about three weeks ago. What age can I sex them? I figured around 3-4 months, but just wanted to check. I read online that the male guppy fry had a more pointed anal fin and the female fry has a rounded anal fin. I looked at my guppy and its pointed, so its a male? Thanks for the help.

Unfortunately, you can't really sex swordtail fry until they are older (at least about 4 months old.) At that point, the males should start having their anal fin rolling up to become their gonopodium. The real problem is that not all males in a spawn will mature at the same time. The more dominate ones will change and grow their sword and keep their siblings from maturing. The best you can do is watch for which fry become larger faster as these will most likely be females. Once the males start showing their "true" selves, you'd be better off separating them into another tank so the other males can mature. This needs to be done in a different tank as they are giving off a hormone to keep the other males from developing. Just putting in a divider or net won't stop this. Only a different tank and a water change will.

As for the Guppy fry, it's 50-50. The fin shape is not always a good indicator. There is no doubt however with a gonopodium

Hope this helped...

 

[Samzter]

Yes all babies start off female but some will change into male. Wait until 4-5 months.