A few question about livebearer fry

So i'm looking at my tank full of guppy, platy, and variatus hi-fin fry and I notice they all look female. Does this change as they get older? when can you tell? Also there are a couple platy fry that look like they have a birth defect   what should I do?

How big are the fry? I get a lot of females from my pandas, but a good mix from my sunburst. I'm not sure why that is... tank temperature can make a difference, but the temp is the same between the 2 tanks, so that can't be it.

Broken fry can be either fed to fish that are large enough to eat them or euthanized (clove oil). Often times birth defects can work themselves out - they die and become shrimp food in my tanks. but other times it becomes necessary to help them along.

I haven't kept detailed records on age of my fry, but I can say that you should be able to tell the sex by the time the platy is about 3/4" in length not including tail.

My fry are pretty young, the biggest is about 1/2 inch. The ones that look defective have like a kink in their back or a strange looking belly, these ones have stayed much smaller, but swim around and eat just fine.

Yeah... I occasionally get the "broken back" looking fry. They dont live long as when they get a bit bigger swimming becomes to difficult. Cull em now and save them the hardship. I have never bothered to figure out how to ID Platy's as all the ways people tell me suggest my community tank has 100% males but miraculously I get fry lol. Guppies you wont be able to tell till their a bit larger when the males gain more color and the females get that rounded belly and dull coloring remains.

Missgrumpygills wrote:My fry are pretty young, the biggest is about 1/2 inch. The ones that look defective have like a kink in their back or a strange looking belly, these ones have stayed much smaller, but swim around and eat just fine.

1/2" is a little small to be able to tell. At about 3/4" you'll see the anal fin fully extended in females and you should be able to see the beginning of gonopodium formation in males. Just look for differences between the anal fins of fish at that size. If you see one that doesn't extend as far and seems to be pointed a bit, it could be a male.

These fry with a gonopodium are usually sexable at around 8 to 10 weeks.
The forward anal fin (the gonopodium) will start to take the shape of a triagle with a slight point, then a spear, then a stick.
A backlight or an observation vessel is nessisary to see this. I separate ALL fry at around this age. Male Guppys with color will be obvious as the males will all show better color at an early age.
Platies, Mollies, Swordtails, Endlers, will take on that shape i've described above and the behavior of their parents.
Good luck

pbmax wrote:Broken fry can be either fed to fish that are large enough to eat them or euthanized (clove oil).

 So, how do I do this?

I used the method here:

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Whenever they said "add x drops more" I'd also shake those drops up with 2 cups (1/2 pint) and slowly add them to the water the fish was in. I used a fairly small holding bucket for this - maybe a gallon of water in it before I started adding water mixed with clove oil.