You are doing just fine then 
After the first week max, move them to a net. They are fine, but still create a dirty enviroment because the little holes in the net do get a bit dirty. But it's better. The only thing is if you move the fry out of it, careful for the fry not to get stuck between the plastic and the net(this can happen if the fry are very small). I have a very small net that I can use to net them out when cleaning a net type breeder box. I have kept guppy fry in a net for up to 4 weeks with no problem but you still have the follow the same maintainance as for the plastic box.
The would grow faster in their own tank though than in a breeder net.
As for the pinned tailed fry, he may, he may not be ok. Watch if some of the rest start developing the same signs in case it is contagious. Hopefully his tail was just bitten before you saved him from the adult monsters
If you have a magnifying glass you may be able to see.
After the first week max, move them to a net. They are fine, but still create a dirty enviroment because the little holes in the net do get a bit dirty. But it's better. The only thing is if you move the fry out of it, careful for the fry not to get stuck between the plastic and the net(this can happen if the fry are very small). I have a very small net that I can use to net them out when cleaning a net type breeder box. I have kept guppy fry in a net for up to 4 weeks with no problem but you still have the follow the same maintainance as for the plastic box.
The would grow faster in their own tank though than in a breeder net.
As for the pinned tailed fry, he may, he may not be ok. Watch if some of the rest start developing the same signs in case it is contagious. Hopefully his tail was just bitten before you saved him from the adult monsters
If you have a magnifying glass you may be able to see.
I hope it comes by then. As soon as they are 3/4 weeks old they can go into the main tank. My platy fry grew unbelievably quick when I let him into the main tank at 3 weeks old. He is now almost 6 weeks old and almost 2 cms long. 
I am so stupid and so angry at myself I let that happen. I usually hook one side of the trap to the thermometer. I can't believe it, what a tard I am. One of them is too fast for me to catch then the swordtails were chasing it. I hope the 3 survive. I haven't seem them it's been an hour 
Don't beat yourself up about it. One time, I put a couple fry into the main tank to see if it would be safe for the others. Later, I managed to net one of the them and put him back into the breeder net, but I never saw the other again. Accidents happen, and all you can do is learn from your mistakes. 
