Unknown fish disease

Hi,
I noticed my Gourami had small hole on its side and a brown string was coming out of it. The string drops and continusly keeps dropping. For 3 days now.The fish is eating and swimming like normal.
I just added API general cure to my tank last night hoping it stop. Just incase it was parasite. The strings aren't slowing down.
Can someone please identify what is?
Thank you.

My tank is 40 gal
Housed with 4 gourami's, 2 corycats, 2 bristlenise plecos, 4 tigerbarbs & 1 algae eater
MY PH level is 6.8

need more pictures and a short video

Water parameters?

Ph-6.8
Amonia-0.25
Nitrite-0.5
Tempature- 78

I'll try get a video tomorrow. I read other forum. Someone suggested it could be fistula. Since it looks like feeces coming out his side.

Looks like flukes. See how the General Cure does.