Funny Thing With Angelfish

[$hiny Fish d00d]

I love my angel fish, he/she is doing well but I have a question on a wierd thing it does.

Say when I walk into the room and it sees me, or if i open the lid to feed it, i can whatch a jet black stripe delvelop at the base of it's back fin, its kinda cool! it normal colour is a pale shiny bone colour...........but sometimes it will also change colours a bit all over it's body its always when it thinks its going to be fed, but extremly black when it sees the food and starts flying across the tank for it.....I was just wondering if this is at all normal and/or anybody else noticed this on their angelfish?

A picture of it normally here:

[Lisachromis]

I'm sure it's just mood dependant stripes. Many cichlids look different according to their mood.