Need an ID???? Whatever this is encrusting it looks Radioactive.

[N4sty T4te]

This stuff is similar to coralline, came in on a wild colony. It seems to be thinner and faster growing than coralline though. It's a radioactive Orange, literally brightest I've ever seen. It's brighter than even say a Jack-o-Lantern Lepto.

What is it!?! More importantly please tell me that I can keep it.

 

[SalinFL]

Sweet! I don't know what it is (sorry), but I hope someone says you can keep it too.

 

[Mike N]

Pretty sure its coralline and yes you can keep it! I got some on rock that came from gulfliverock.