Kole Tang is thin -- how to treat?

My Kole Tang is eating fine, but is really thin.

I did QT for 4 weeks doing 1 regiment of prazipro.



Has not gained any weight in the last 2 months that I was hoping, so I think it could be a parasite. I am feeding NLS pellets in the AM, then either flake or mysis in the PM with seaweed every other day (which she barely touches anyway).



I am not sure what to do so I need guidance.

What products? What treatment? What should I do here?



Thanks