Any idea what happened to my friends coral?

[Mark03]

 

[happyhourhero]

I would check your friends alk and go from there

 

[smh254]

Yes check alk and for pest.

 

[Y&Y Corals]

Also tell him to check for emerald crabs they tend to do this stuff to corals

 

[xilez]

Not sure what pest would cause that uniform of damage.

I'm leaning towards Alk swing

 

[OnPointCorals]

looks like it got stung. was it next to another coral?

 

[Nickster135]

This happened to me when I put a birdsnest too close to frogspawn. Moved it away from it and it fully recovered.