Big Female, Pregnant?

I have a full looking female and I’m thinking pregnant. I recently lost two Molly’s and I’m down to two females and 1 young male.

Since they are livebears does that mean she got pregnant before the older males died. Or would that be all eggs?

 

Yes, she could have been impregnated before the males died. She could even be pregnant from the young male.
Females are usually more rotund because of the eggs, but she is looking pregnant to me.
Platys are prolific breeders so I would not be at surprised if you have fry very soon. Congrats, your gonna be a fish grandparent!

 

Yes, she could have been impregnated before the males died. She could even be pregnant from the young male.
Females are usually more rotund because of the eggs, but she is looking pregnant to me.
Platys are prolific breeders so I would not be at surprised if you have fry very soon. Congrats, your gonna be a fish grandparent!

Any idea how long I have.
I got one of those separation containers that go in tanks. I don’t want to stress her out having her in the small box too soon.

 

I went through some of the Fish Lore forums to see how long their gestation period lasts and it seems about a month or so. She's pretty far along but I'm not sure how much longer she'll be carrying. Do you have a QT tank you could put her in instead?

 

I just setup a 10 gallon tank but I'm concerned that it hasn’t cycled and the water isn’t good yet. I picked up a 7” isolation breaker box. My other fish are usually hungry in the tank so I be lucky if I find one or two babies the next morning

 

If you have plants or little rocks/crevices for the fry they can hide from the adults. When I had platies they bred so quickly that predation could never reduce their numbers enough.
I don't know if you have any cycled media from your current set up, but you could try putting something of that in the new 10g. I recently set up a 5 gallon tank using 100% water from my 20 gallon along with cycled sponge filter, plants, rocks, and driftwood to speed things up.
Don't stress too much, though! Sounds like you are doing everything right and everyone is happy