How to identify Frye molly gender?

[TO KYO]

In May 6, 2019, my black molly gave birth to over 30 baby mollies and since then I’ve been patiently waiting for them to grow big enough to reveal their true colors and genders so I can decide which ones to take. I gave 2/30+ babies to my sisters so she put them in her tank... today her tank cracked so I had to take all her and put them in my tank meanwhile. And that’s when o discovered that one of the two babies developed his male peepee, but all my fish still looking the same?? I can’t believe all others brothers are females.
Or

Could it be that isolating them makes them develop faster?
My babies developed better colors. Her’s haven’t yet because she feeds them the same stuffs and her tank is smaller (10g)
I also heard mollies could change from female to male or the other way around.
Sorry for the long post, my writing skills sucks

 

[Colin_T]

Mollies don't change sex but female swordtails can become males if there are no males in the area.

Chances are your fish are too young to sex. They don't become sexually mature until they are about an inch or more long (not including tail), which might be 3 months of age.

If you have a dominant male in the tank, he will harass the smaller males and they will develop slower. Females have a fan or triangular shaped anal fin. The males have a modified anal fin called a gonopodium, that is long and straight.

The fish you circled in green appears to be a young male. Most of the other fish look like females, based on their body shape. Give them another month and see how they look then. You can identify young males by their behaviour, they will chase the females and try to breed with them.

 

[TO KYO]

Mollies don't change sex but female swordtails can become males if there are no males in the area.

Chances are your fish are too young to sex. They don't become sexually mature until they are about an inch or more long (not including tail), which might be 3 months of age.

If you have a dominant male in the tank, he will harass the smaller males and they will develop slower. Females have a fan or triangular shaped anal fin. The males have a modified anal fin called a gonopodium, that is long and straight.

The fish you circled in green appears to be a young male. Most of the other fish look like females, based on their body shape. Give them another month and see how they look then. You can identify young males by their behaviour, they will chase the females and try to breed with them.

They were all borned the same day, yet this one developed anal fin and is already trying to breed with the other babies

 

[Colin_T]

Separate the one that is trying to breed with the others. You should also separate the father so he doesn't breed with any of his daughters.

 

[TO KYO]

Separate the one that is trying to breed with the others. You should also separate the father so he doesn't breed with any of his daughters.

Why, deformation? My tank is almost overstock, so any new fish will become Oscar dinner

 

[Colin_T]

Fish (and any animal) should only be bred with unrelated members of their own species. Inbreeding (father and daughter, brother and sister, grand mother and grand son, etc) should never be done due to the risk of deformities and reinforcing genetic defects that would normally be reduced when breeding unrelated specimens. Inbreeding only weakens a species and increases the risk of future health issues.

 

[Back in the fold]

Gonopodium. If the organ itself can't be long the name can.

 

[fish48]

Fish (and any animal) should only be bred with unrelated members of their own species. Inbreeding (father and daughter, brother and sister, grand mother and grand son, etc) should never be done due to the risk of deformities and reinforcing genetic defects that would normally be reduced when breeding unrelated specimens. Inbreeding only weakens a species and increases the risk of future health issues.

 

[fish48]

it's very rare that I find any problems with inbreeding fish, it's a fish keeping myth

 

[Colin_T]

It's not a myth. I have seen it in rainbowfish, barbs, cichlids and livebearers. There are unseen genetic changes, visible physical changes, and the fish generally have a shorter life span than fish produced from unrelated parents.

All animals suffer from inbreeding and fish are no exception.

 

[fish48]

I agree with you to a certain extent my only interest is of the inbreeding of fish what you say about inbreeding can happen it don't mean it's going to happen

I disagree with you saying that you should only bread with unrelated fish as you know all of the cultivated livebearers have already been in- bread so by putting two unrelated cultivated species together is it really going to improve things
and bear in mind that some fish are not genetically compatible which can also create deformities and it’s not long before ones fish tank is overcrowded therefore many fish will end up back at a Pet Shop so unrelated or not the process of inbreeding will start all over again

 

[fish48]

This strain of guppy as been inbred for more then 20 years and with no problem
the record for a strain of inbred guppy is100 years

 

[fish48]

A wild type guppy inbred from a 1976 collection.
when it comes to breeding fish and to say that you should never breed related fish such as brother and sister etc and all the crap about it weakens them causes deformities and short-lived these problems can occur but very rare inbreeding fish is not a problem it's mainly down to people not understanding what they're doing with the fish