Green Severums

[the caretaker]

I have 4 Severums 2 have paired off and have spawned for the 1st time but the male has 3 tiny little white marks on 1 of his fins.
How can I treat him with out killing the fry? it look like it might be fin rot theres not enough to be white spot. although it might be where they were getting friendly.
Any help would be great thanks.

 

[Dwarfs]

You should try to treat him separately as not to risk the fry The female should be able to keep an eye on them