What is this Christmas Tree worm doing?

[kwan]

My Christmas Tree worm is behaving strangely. It keep retracting back into its tube probably because of unwanted attention from my fish. But when it comes out again, the two crowns seems to alternate in color. One is white and the other is sort of pale grey. And the color rotates between the two crowns every 15 seconds or so. You can just see from the pictures the tone of the crowns have switched over. Any idea what is happening here?

 

[seaham358]

Coco worm..... I would not worry about it, it probably adjusting itself trying to get food.
If the crown pops off then it is stressed and something maybe wrong.
Cool worms.....