Can try metroplex or kanaplex in food. It won’t be as effective if an external bacterial infection. Any other fish showing any signs and also on the topic of shrimp - do you hear any clicking in your tank?
https://www.reef2reef.com/threads/metronidazole.298762/#post-3655831
https://www.reef2reef.com/threads/metronidazole.298762/#post-3655831


