Question: Black thread?? Out of its side.

Hi everyone.
I rescued a baby .. not in great shape no gills etc. But I'll address that elsewhere.. later. Hes is doing ok right now. But eating .. he wants to he tries hes super tiny yet I know he is atleast 4 months old if not older.
But as I'm trying to figure out all his quirks.. a while back it looked like a thread kinda floating out of his right side in front of his hind legs I'm assuming intestines area maybe.
I wiped it gently away..
But its bugged me forever and tonight I git part of and a really good picture and it actually looks different now.
I touched the part I got off its like a very thin very stiff thread. And then I looked at him and there was a good bit out of him. So I got the pics.
It diesnt move are anything.. so I'm not thinking worms it soooo thin and stiff. But must be super long. It almost makes me think no weight gain etc has to do with this thing maybe packed inside him. Yuck. And poor thing!

This looks like Anchor worm and is treatable. Here is a link with what to treat it with.

http://www.caudata.org/cc/articles/illness.shtml

Ahh thank you! I have never dealt with an anchor worm before. I have found a product Dimilin X on amazon people seem to be recommending on other posts on here.
Issue. He is in a holding tank while the large permanent tanks are being cycled. He was a rescue so hes in I think it maybe a half filled 2 gallon "critter keeper". The instructions I have seen alittle of says dont change the water but I have to change daily. No cycled water and no filters. I cant get a extra small sponge filter to help.
Any ideas? Is this also why maybe he hasnt growing or getting better? I dont know anything about anchor worms. And oh hell dosage kn. That tiny of a tank.. hmmm
But thank you and any recommendations or ideas would be wonderful!!