/www.fishforums.net/index.php?/topic/380467-is-my-oscar-ok/
Given the lethargy and flicking, I'd say he's got gill flukes.
/i.imgur.com/aEgVK.jpg to try and treat gill flukes on my oscars i have to treat it with this over the next ten days i will update you guys if you want in the next 10 days and ill tell you if it has worked or not i hope it does the trick