Worm tube thing in fish

[Scozi]

Sorry if this is the wrong place to post, I'm new here. But there's this tube like silvery thing that's hanging out of my swordtail, anyone knows what this is? And what can I do about it?Screenshot_20190623-213606_Gallery.jpg

[Scozi]

Here's a better picture, he's not emaciated or anything and he's pooping at the same timeScreenshot_20190623-214335_Gallery.jpg

[Guppendler]

That’s the genitalia of the male sword called gonopodium