Context:
3 gallon aio
Only other corals are a small Duncan.
Had in there since may and he was doing great opens up every day and looked amazing. Then I wake up this morning and I see this. One of the head is just gone. Bear with me I am new to the hobby but is it just closed or completely dead. Both nitrates and nitrites are 0 ph is good. Water temp is stable. Flow haven’t changed. What is going on? Should I chop that head of?