Why are parts of my Red setosa bright green/yellow under UV

[nathanb25]

Hey!
So I noticed some of my red setosa turning brown but last night while adjusting lights I noticed parts of the RS were bright green/yellow.
What is this?

 

[Alex Cataldo]

Is this the first time you’ve seen them under UV?

 

[nathanb25]

Is this the first time you’ve seen them under UV?

No, I’ve seen it before and the patches were smaller.