Duncan coral question

Falcar · Aug 19, 2019

Hey all:

I had a Duncan coral (3 heads, one was 2" or so across), that seemed to be doing great. Then yesterday morning the heads never came out, and half the coral was bleached.

Now it looks completely dead. Any ideas on what might have happened?

My alk is 9.3, calcium 430. The only thing a bit high is nitrates at 25.

I'm at a loss.

Lorenzo Angotti · Aug 19, 2019

Hi, I had similar thing happen to my Duncan, when bought it had two heads. I placed it pretty low, medium to low flow and was doing great, it developed about 10 heads and all of a sudden it started to retract and remained like that for a while. I too had Nitrates problems being on the high end and still battling to try bring it down. Now the Duncan even though it remained retracted you could still see that there was life in the centres. It took nine months when my Nitrates were a little better that the thing came back to live and started to flourish, and a few months later it’s started to do the same thing retracting again and when checking my Nitrates again they were up. Duncan’s don’t like Nitrates above 10ppm.

CindyKz · Aug 19, 2019

I don't know if I would pin this solely on your nitrates, my duncan was never bothered by them. Do you have any clownfish? Sometimes they'll use a duncan as a substitute host if there isn't a suitable 'nem available (or even if there is). I lost a really nice 40+ head Duncan that way.

LIreefguy · Aug 19, 2019

its sometimes hard to pinpoint why a coral grows for us then all of a sudden dies, but make no mistake its most likely water chemistry issue. your nitrates are high, while some might tell you they have nitrates at 25 and there coral grows, others will tell you nitrates will kill

it could be both. you see maybe his nitrates are 20 and yours are 40 with testing error, so hard to see color on those test, lol

maybe his tank, flow and coral is healthy than yours , maybe his nitrates say close to 20 while yours jump from 20-50-25.

i find my tank does best when i test everything once a week and do a water change once a week.. this is not me saying everyone has to do that, just saying what i notice.
my problem is i have 50 fish in my tank, i love fish. when people come to my house, even experienced reefers they are always like wow you got a lot of fish. my 6 barlets are huge, my 11 tangs are pigs, my 4 bimac are beautiful and large. so i always have issues with nutrients. if i am not on top of them my sps start dying.

find what works for you. dont judge success on your coral doing well for 3 months or 6 months. healthy corals will grow like weeds, a duncan can go for 2 heads in 20 heads in a little over a year.