A better pic would help, but that doesn't look like Ich to me. I also believe it is either fungal or bacterial.
Can you set up a QT/hospital tank for the clown? Start is off with water from your tank and make enough sw
mix to do daily 10% water changes if you don't have filter material from your tank that can be moved over. 10% daily pwc
in a hospital tank is always a good idea anyway...