Gill flaring problem

This afternoon I noticed my betta Mr Bojangles doing his flaring dance for me, and only his left gill flared out. A second or so later the right one flared out. This happened every time he swam by me and did his flare dance. I looked closer at his right side, and there's a whitish line, (not spotty like ich) about 1/2 cm long, on his gill. Bo is in a 1.5 gallon heated betta bowl at work, I've had him about 3 months. I know bowls are bad, but he's at work and my options are limited. I do a 100% water change every week, and apx 20% changes 2 or 3 times a week. Has anyone seen this before? I hate to exaggerate, but I'm crazy about this fish and I don't want him in discomfort and I CAN'T lose him!

 

One of our bettas, Aslan, could only flare the one side of his flaring gill for a while and coloring is normal on the flaring gills - is this for sure something new?

 

The one-sided flaring is definitely new; he was flaring normally this morning. As to the white line, that may not be completely new. I think I first noticed that a week or so ago, but just decided to watch it. He was and is acting normally otherwise.

 

Aslan did flare normally, then he started doing the 1-side flare.. it was like he "pulled a muscle".. eventually he got the normal flaring back. would you have a pic of the white line that you could post?

 

Bo's tricky to photograph, round bowl and all. He'll dance for ME, but doesn't like the look of the camera! I'll try tho. He's unchanged today, still doesn't ACT ill, so I'll maybe treat with an anti-fungus/bacterial, and watch him. Thanks for your reassurance, I was hyperventilating! x

 

Bettas do seem to enjoy frustrating us at picture time. He does sound good and unless that line were fuzzy, i'm not sure of any med that i'd say to give him.. just liquid vitamins like VitaChem if you have any.