Help! What Is That?

[Guppy2206]

My very pregnant guppy recently started hanging out by herself and she got the boxy look, and pointy anal area, so I put her in a breeder box (I know that's not right but...) but now she has this huge pink circle thing coming out of her! Please what is it and what should I do???
Ps her tail is shredded because my half moon betta went crazy after a week of being in with them, ate one of my green cobra guppies and shredded her tail.

 

[WILDER]

Is it her intestines?
Does she look skinny with a sunken in belly?
Is her spine bending, or look curved?
Does she eat well?
Is he anus enlarged, or red and inflamed?
Have you seen any worms sticking out of the anus?
 
Is it a male betta?
Do you have any male guppys  in the tank?
As betta's see them as competition so they will attack them , or even kill them.