Difficult to tell from pics as aquarium glass is little dirty. Look for these three major parasitic diseases that clownfish, and for that matter most other fish tend to get a lot.
1. Ich, officially known as Cryptocaryon irritans - look for small white dots that seem to fall off in a day or two, sometimes leaving behind small circular wounds. Treatment is by hyposalinity or copper.
2. Velvet, or gold dust disease, officially known as Amyloodinium occellatun. Looks like the fish is covered in a coating of gold dust, and the fish is often going around scratching. Treatment is by copper.
3. Clownfish disease, officially known as Brooklynella hostilis. Looks like gray irregular patches. Treatment is Formalin.