Acan corals always dying

[wrenfeathers]

Hey folks
I’m going just over a year on my 5 foot mixed reef
Mostly successful
Fish are super healthy
Motile inverts seems to be doing great, including two sea stars
Sps doing well with growth

However; I can’t seem to keep acan corals (micromussa lordhowensis)
The flesh slowly recedes from the bottom outer polyps and moves up to the top and centre until nothing is left
One managed to pull through with two polyps left and seems to have stabilise but I’ve lost about 5-10 this way

I have one peppermint shrimp but have never seen it near them
I have asterina stars which I often find under the acans. Once I saw an asterina star on the edge of a polyp for a couple of days. When it moved the polyp had receded. Now this colony is going through the same recession of tissue. I was dismayed today when I saw a bristle worm holding on to some flesh which was coming off this colony.

I have also found little white brittle stars under my acans.

I don’t know if any of these inverts are causing the problem or feeding off weak acans. But something is certainly up.
I noticed today that another lps frag, a Moseleya, also had tissue recession.

I do not currently have any wrasses in my tank (for invert/ pest control)

Any thoughts or related experiences will be appreciated. I’m really at a loss since all the other corals are doing well.
Thanks

[CheezotheClown]

I don’t really have anything to offer wren. At a guess I’d be suspicious of something that the species is particularly unhappy about or needs is either in or missing from the system respectively. It could be that something has taken a liking to it as a snack but the bristle worm and brittle stars suggests they’re about to clean up rather than cause the issue, well to me anyway.

Any sneaky crab(s)?

[wrenfeathers]

Yeah I’m with you on that cheezo
Just sent off Icp test so I’ll be interested to see the results of that
Another possibility is my two tangs - again doubt it’s them though

Only small crabs that come out at night but I’ve never seen them on any corals

Thanks for the reply

[johnact]

What corals are near any hammers or a torch?
Also list your parameters.
Acan are one of the easiest corals to keep so if your sps are doing well something is attacking it I would think a stinger from another coral at lights out.
Or the dosing you are doing with solid is getting on the acans.

[wrenfeathers]

Parameters are all pretty good
Nitrate high though at about 20-25

Yeah I keep hearing and reading that Acans are easy but that has never been my experience
For me they have been the hardest with both my setups

It’s either the nitrates or the solid supplementing, which I’ll be changing now to liquid dosing

No corals close enough to sting

Thanks

[johnact]

If your sps are growing and have colour it’s not parameters. How close are all those corals you have posted in classified to the acan all of them can have stingers come out at night up to 30cm I highly think it’s one of them.
Can you post a straight on pic of your tank pls.

[wrenfeathers]

Not sure how to post pics
But none of them are close
Most are on frag rack or high up on the rockwork

[johnact]

You need a photobucket acc or an image hosting then upload your pics select which ones and copy and paste the link in the message box

[johnact]

You need a photobucket acc or an image hosting then upload your pics select which ones and copy and paste the link in the message box

https://imgupload.io/images/2020/12/29/ ... FFDCD7.jpg

[johnact]

Go to https://imgupload.io/ create an account then upload pics to it select pic then use the pic direct link copy the code then paste it into your message photo bucket you have to pay now this one is free

[wrenfeathers]

Thanks John