Duncan coral woes, not opening

The salinity change is a definite possibility. I live in Fairbanks Alaska and as winter approaches it gets very very very dry and evaporation is fairly fast. I add water daily. But considering that I have some rather delicate SPS and LPS in that tank that do not mind the salinity change however small it may be I am going to stick with lowering the temperature to 78. Thanks and keep the ideas coming I appreciate it.

 

also look for anything that might be bothering it i had a small crab trying to eat mine at night

 

You are pouring your water in the exact same manner as I do. Over a Koralia

 

I have an amazing duncan too. I try to keep my temp as close to 77.7 as possible and it is very happy. As the other posters said, I think your temp is too high.

 

Well I lowered the temp from 84 to 78 degrees over the course of two days. No reaction yet from the duncan. Hopefully in a few days it will pop back out. Obersving it at night the poly partially extend from the stony however they only extend like an eighth of an inch, not even close to a full expansion. I tried to target feed it a brine shrimp and there was no interest. No expansion what so ever during the daylight hours. Polyp is sucked into his tube as much as possible. Thanks for the thoughts though!

 

Finally discovered the problem!! My bicolor goby attacks the polyps of my duncan an my frog spawn when they appear!!! i watched him do it every morning for the last 3 days!! hate that fish