Yes. Galaxea Coral needs ATLEAST 6-8 inches of room away from other corals. Sweeper tentacles get long. I’ve seen them get much longer than that actually. And they pack a mean punch on other corals. 9 times out of 10, they’ll win the fight.
I was warned by my LFS when I purchased mine, and eventually got tired of not being able to use the top right side of my tank, and I returned it.
Beautiful coral tho, but man are those sweepers mean