Big white patches on bristlenoses

What are these white patches on these lemon blue eye bristlenoses? They started to appear after my friend got them from the breeders, and is only present on these 3 LFs, the SFs she has currently doesn't have the patches.

Took these pics last December and the patches has become more prominant now. Last two pics taken night I got them (probably under stress) but also under a very warm lighting

Will try to take more pics tomorrow.

Unrelated: I've noticed the male turning a little bit more yellow/orange than the females in the bunch. Is this normal?

 

It looks like a bacterial infection to me, the patches make me think columnaris. If they’ve had it for awhile, it appears to be slow moving. What country are you in?

 

It looks like a bacterial infection to me, the patches make me think columnaris. If they’ve had it for awhile, it appears to be slow moving. What country are you in?

I'm in Australia. The patches are like pigments, there isn't any fluff or growth.

 

It doesn’t look like slimy patches? Thats how it looks in the pics.

 

It doesn’t look like slimy patches? Thats how it looks in the pics.

Nah its not slimy at all, they all feel somewhat like sandpaper texture.