duncan coral closed randomly

[dym]

hello everyone. my duncan closed and looks like its swallowing itsself is this normal? its 5PM so in the middle of the peak and hes been closed for an hour or more. the only thing i can think of is i did a 5 gallon water change yesterday (my tanks 125g) but the salinity matched eachother, which is 1.026. my nitrates are between 5-15 and its not swallowing food in the picture. i also moved it toward the center of the tank so it could get more light since my light isnt too strong 3 days ago. second picture is him normally

 

[dym]

btw he didnt look too good before this, his tentacles got thinner

 

[Uncle99]

Way to blue to see much but the behaviour seems normal to me.
Leave it.

 

[Tahoe61]

Honestly I stopped worrying about why my Duncans close and open randomly years ago.
They are extremely hardy corals. Unless water chemistry is way off or they are being over illuminated Duncans are hard to kill.
Double check or calibrate the device you use for measuring SG. Or try moving the coral back to where it originally was.

 

[Marine Betta]

hello everyone. my duncan closed and looks like its swallowing itsself is this normal? its 5PM so in the middle of the peak and hes been closed for an hour or more. the only thing i can think of is i did a 5 gallon water change yesterday (my tanks 125g) but the salinity matched eachother, which is 1.026. my nitrates are between 5-15 and its not swallowing food in the picture. i also moved it toward the center of the tank so it could get more light since my light isnt too strong 3 days ago. second picture is him normally

Duncan’s are weird. Mine will close all day, open at night, and then stay open for the entirety of the next day. If it were to be closed for several days in a row, I would look into it. Are your other parameters in check (i.e. Ca, Mg, and Alk). They also don’t need a ton of light, but leave it and see if he adjusts to the new spot.