How Old/big Before Transfer

[daveg6529]

I have four platys in a 40ltr tank with a separate area. Two weeks ago one of them gave birth to about twenty fry. I have put them into the separate area and they all appear to be healthy.
I also have a 260ltr tank with small tetras and corys in.

At what age or size would it be best to transfer the fry to their new home? & how many can reasonably be expected to survive?

Both tanks have identical levels of PH, Ammonia, Nitrite although there is a slight difference in the Nitrate levels.
40 ltr - 80
260ltr - 40.

This is the first time I have been in this position since starting to keep fish a year ago.

 

[FreshwaterAfishianado]

Once you feel that the fry are no longer able to fit into the mouths of any fish in the main tank you can reintroduce them. As far as survival it depends mostly on keeping pristine water for fry.

 

[Ny82]

I put my guppies into my big tank at 2 weeks old. I found that having them in a separate tank made their growth rate impressive. They went into a tank with adult guppies. They were chased for a few moments then the adults started to relax and accept them
 
I find with platy fry they grow a lot slower so like freshwaterafishianado said above, as long as they don't fit in any other adult fish mouths (the cories are fine) then they will be fine. Platies are the masters of stealth anyway so will instinctively hide. 

 

[snazy]

Actually, platy fry grow very fast. I don't know what size yours are at the moment but in another couple of weeks there'll be nothing to eat them. They are smart enough too, so they'll run and hide.
 
If you've got just tetras and corys, I'd say they may be good to go now. Just feed them before you put the fry in. Then turn off the ligths to let them find hiding places.
 
Survival rate of platy fry can be 100% in a non-predatory tank unless you get the odd case of deformity or something else. That's providing the tank they are in is completely cycled.

 

[josh63762]

I would wait about 3 weeks to a month depending on how often u feed them in order for fry to grow fast you should feed them at least 4 times a day