Moorish Idols are very difficult to keep even for the most experienced reefers in very large, established tanks. I hope for the best with your specimen. Mandarins also prefer older tanks with well established pod populations. Has your tank been only set up for 2 weeks or 2 weeks past cycling?
How are you treating that eye infection? Since the Mandarin and the Idol have experienced eye problems, have you checked them for flukes (although flukes usually show up in both eyes, not just one.)