What is eating my acros?

[Fenzinna]

Last night vs this morning. I have a few frags that are starting to miss nubs like this blue voodoo below as well.

before is bottom. This was two days ago vs yesterday. Nub on blue voodoo went missing during the day. Top acro had chunk go missing at night.

Help! I can't figure out what's doing it.

 

[Fenzinna]

It's a 130 5ft.
Spot swallowtail angel
Fire fish
Bengai cardinals x2
Two clowns
Two wrasse
Midas blenny
Lawnmower blenny

Hermits
Snails
Strawberry crab

Tank is about 2 months old. Started with half dry rock and half live rock. Cycled together and had 2ppm ammonia spike.

What could take off whole chunks like this?

 

[reefrider777]

Maybe gorilla crab