Fin Rot With Fry

[Neptune54]

My fry are almost two weeks old now, and I'm almost positive that one of my guppies has fin rot (the fry are in a breeder net inside of the community aquarium). Can I treat the guppy? I don't have a hospital tank, by the way. The fin rot's not bad, and it might even be a nip from the pet store, but if it is, I'd like to treat it. If it helps, I've also got two platies and two guppies.

 

[OldMan47]

If it is a nip or similar damage, keep the water pristine and the fin damage will heal.

 

[Neptune54]

I'm fairly convinced that it's fin rot, since it seems to be getting worse. If the other fish have been nipping him, I haven't seen them.