Why are all my baby platys female?

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23578

Aquarium Advice Regular
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Nov 15, 2021
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I got some male and female platies about 10 months ago, and they've been giving birth consistently since then, but for some reason in all that time I've only ever had 2 males be born vs probably 30+ females. Does anyone know why this might be? I just think its interesting and wondered if there's an explanation or its just a coincidence.
 
I found a high pH (above 7.6) increased the number of male offspring in soft water fishes. I never tried it with livebearers.

How big are the babies when you sex them?
Young male livebearers look like females until they become sexually mature around 1 inch long.

The other option is genetics. Your fish simply produce more female young because of their genetics. It's a bit like a couple of people having all boys and no girl children or vice versa.
 
The temperature in the tank is always right around 78 degrees and the Ph is around 7.6 normally. I usually sex them when they're a couple months old, at least an inch long. Most of them I'm sure are females because they're pretty old, but there are some babies that are small and maybe could turn into males.
I also was wondering if maybe it has something to do with how quick the babies are right when they're born because I just catch any babies I see with a net and put them in a breeders box, so maybe the females are worse at hiding and I'm more likely to see them and catch and raise them, and that could maybe be why.
 
The temperature in the tank is always right around 78 degrees and the Ph is around 7.6 normally. I usually sex them when they're a couple months old, at least an inch long. Most of them I'm sure are females because they're pretty old, but there are some babies that are small and maybe could turn into males.
I also was wondering if maybe it has something to do with how quick the babies are right when they're born because I just catch any babies I see with a net and put them in a breeders box, so maybe the females are worse at hiding and I'm more likely to see them and catch and raise them, and that could maybe be why.
Adding to Colin's comment about Genetics, you also have to consider that fish have the ability through hormones released in the water to suppress maturation of rival male siblings so you need to do frequent water changes or separating all suspected males from each other to get these males to maturity faster and then they can be housed together. Don't forget, an immature male looks like a female. :whistle:
 
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