Aquariums: Does my tetras have Velvet disease or do they glow naturally?

I've lost 2 Bettas in my tank to Velvet disease. The two tetras have outlived them both. I can't tell if they are carriers of the disease, since they "naturally" have a glow to them.

I'm now disinfecting my tank with medical stuff but I would like to know if they look "normal", as to look out for any change. Pictures are taken with flash on.

I've uploaded a picture of my previous Betta too for reference (who was heavily infected).