Please help my betta has a white stripe is he sick?

[Sguelly]

My one year old betta fish Sushi has a white stripe on one side of him.
He is eating regularly He is currently the only fish in my 5.5 gal tank. Just had the water tested and was told it was fine. I am using a top fin filtration unit that came with the aquarium kit. I do a partial change of water every 2 weeks including vacuuming the gravel. I have tried 2 treatments of betta fix doing a complete water change after each treatment. Please see attached photo. Any advice would be welcome.

 

[SaraB]

Try changing 50% of the water weekly. It doesn't look fuzzy so it might be bacterial and not fungal. Clean water is your best friend. If you have aquarium salt then you can add some in or do a salt dip and it might help.

 

[Sguelly]

Try changing 50% of the water weekly. It doesn't look fuzzy so it might be bacterial and not fungal. Clean water is your best friend. If you have aquarium salt then you can add some in or do a salt dip and it might help.

Thank you, I have no aquarium salt right now, but will pick some up. Until then, I will try the more frequent water changes.