What is this on my Duncan?

[DebFerreira]

This Duncan is in a 13.5 nano with stock lighting kept on blue (except for this pic) plus two smaller blue LED supplemental lights. I just noticed this today.

 

[rhostam]

Those are mesenterial filaments. The guts.

https://reefs.com/2011/07/23/when-c...nd kill prey, and to sting their competitors.

 

[DebFerreira]

Thanks for the reply, and the link. I was worried that it had some sort of terrible infection.