Intestinal Parasite or fish poop?

I have a 20 gal tank with wcmm and just decided to add guppies. The place i got them from was like a mom and pops fish store so I thought it would be okay to just add them in. Now that ive been looking more at the females I noticed some have this sting coming out of them but only them and I know that can be a sign of a internal worms so now im worried that its infected my entire tank. But it also looks like it can just be poop because I also gave them colored fish flakes and the string stuff that fell is everywhere in the take and around the same color as the food i gave them. The sting by the way is a light pink color almost a red and certain parts of it are a little whiter or more red then others this is why I think it might be poop too.

Not an expert on these fish but I would say a parasite. Definitely going to need a second opinion though because, again, I'm not an expert lol. @Colin_T should be able to help.

Share updates if anything significant happens.

probably worms, livebearers are riddled with them so just deworm all your tanks.