Clownfish internal parasites?

[Giantclownfish]

I’ve had a clownfish for about 5 months and it has had a white stringy poo for a while, so my first response was to dose metroplex and prazipro until symptoms disappeared. After a week or so the symptoms disappeared so I stopped medicating the water. Shortly after that the symptoms came back and I decided to try the API general cure. I followed the instructions on the pack which suggest 2 doses and the clown still has the white strings. What else can I do? I don't know what else to try.

 

[Giantclownfish]

Also, she was not eating for a while and recently started eating again.

 

[vetteguy53081]

Also, she was not eating for a while and recently started eating again.

Often when you feed mysis shrimp, brine shrimp or both- it mimics intestinal issues which are the foods.
What foods are you feeding.
How long did you use the metroplex?