swelling guppy

Question
hello,
I have a female that was very big, and I assumed she was pregnant and moved her to "fray box" after 3 days and no babies I moved her back to the tank, all the males kept attacking her belly so I moved her back to the fray box to give her some time,
then I noticed that he body became tilted and that she can't swim and her fin is always on top of the water,
there is like big bubbles of air, and blood vessels that I can ,
can you please tell me what it is, and what I can do,
I'm treating the tank with fungus medication and added aquarium salt and changing the water very frequently
thanks

My tank is 20 gallon, and I change the water 2 times a week (75%)
and change approximately 10% every day,
as I have like 15 guppies in that tank

Answer
Hi Hanin
So, you do water changes of 75% twice a week and also change 10% everday?  That's a lot lol....you could probably cut back to two changes weekly at 25%.  Actually, 15 guppies in a 20 gallon tank, with good filtration, it's not that bad really.  Just make sure like I said, there's good filtration, and don't overfeed them.  

I'm sorry, you gave a fairly good description, but I'm having a hard time picturing what you said.  
The body's tilted-meaning she's on her side-is she swimming this way or floating or sinking to the bottom?
Fin is on top of the water-meaning, she's hanging out on the top with the fin sticking out?
Big bubbles of air and blood vessels-where are you seeing that?  
And, is she still big like she's pregnant?  Or did her belly go down?

And, why are you using the fungus meds-for this problem or for something else?

Christy