Zebra Danio - red thing coming out of from behind anal fin...behind

[woofwoofgrrl]

My Zebra Danio has a red thing extending out from behind his anal fin - it kinda looks like a stuck red poop.... otherwise he seems to be acting fine. I just fed him some pea incase he's constipated... Should I treat for intestinal parasite?

 

[trackfast]

I think it's Callamanus worms. Levamisole is usually used.