Can 2 Duncan’s be close to each other?

[deadboi77]

About 2 months ago,I added another duncan,about 3-4 inches from another. The 1st Duncan has been in the tank,will be 2 years this April. And since then,it’s been kinda closed up. It’s still eating and parameters have been pretty stable for almost a good year(tank will be 2 this March. I see no pest or anything that could be bothering it. New Duncan is all good though and both are the same species.
Thoughts?

 

[KrisReef]

I kept one and grew it up. Along the way it seemed to act differently now and again but I never did understand what made it inflate, deflate, or open up more or less while I had it. I kept fragging it and moved it around a bit but it hung in there and did what it wanted to do. It was super hardy compared to other corals but it did act up now and then, it was alive so I let it do what it wanted along the way.

 

[Lps_lover12]

I have two colonies of Duncan’s right beside each other, no issues and both open up fully each day

 

[exnisstech]

I have 4 touching each other with no problems.