Angelfish spot

Hi guys any ideas what this mark on the head is? Noticed it today.

Can you post some more pictures of the fish from both sides and check them on your computer to make sure they are in focus?

It could be the start of hole in the head disease, which is caused by poor water quality, dirty tanks and dirty filters.

What are the tank dimensions (length x width x height)?
How long has the tank been set up for?

How long have you had the fish for?
What other fish are in the tank?

How often do you do water changes and how much do you change?
Do you gravel clean the substrate when you do a water change?

What sort of filter is on the tank?
How often and how do you clean the filter?

Have you added anything to the aquarium in the last 2 weeks?