Betta fish electric currents?

Question
Okay i know they aren't electric currents but it sure looks like it sometimes. I just got this little guy about a week ago, a very nice looking halfmoon with green body, red fins and white accents on the fins. Ive been having a hard time getting him to eat but in searching how to help them eat i read to excite him with a mirror, and its working great. Today during his food attacks, i noticed the top of his tank was crooked so i fixed it but it suctioned closed in a sort of deep pop way. He was already puffed out(i dont know the correct term for this) but at this moment he started like shimmering for about 15-30 seconds, and the only way i can describe it is like electrical currents, like i said in the titling. My question is, was this some sort of reaction to the loud sound the lid made, or was it possibly just how my fish looks when light hits him right?

Answer
Hi Andy,
  Most likely it is a matter of the light, but noises can also inspire a male betta to pump up his colors.  They certainly are impressive when they do their shimmering thing.

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>