acan recession

I have 5 acans in my tank. all 5 have been doing great, but then yesterday I noticed that two of them were recessed. Just checked and they remain recessed. The lighting and flow that they are receiving has not changed and are relatively consistent with the other 3 acans that are doing well. All other corals (SPS and LPS) seemed to be doing well. Should I be concerned.
Parameters are great with exception that Mag and Calcium might be a little low.
PH 8.2, amonia = 0, nitrite = 0, nitrate, =.02. KH = 220, Calcium 400, magnesium 1300. This was based on parameters checked last night. I have since added calcium and mag, but have not checked it.

 

by recessed you mean they are starting to show skeleton or the polyps are just contracted?

P.s: acans are LPS

 

I have 5 acans, did I post to the wrong forum?
They are contracted and with one as a result of being contracted I see skeleton.

 

They are LPS and I'll move the thread to the correct forum.

A day or two of not be as extended is not worrisome. When they stay that way or you start to see skeleton than you need to start trouble shooting.

1. Looks for the presence of larger type amphipods and other pest at night.
2. Some inverts such as cleaning shrimp can decide Acans taste good, some fish types such as Angels can also develop a taste for them.
3. Are there any near by lps or other inverts stinging the coral.
4. Continue to monitor water parameters and consider the addition of larger then needed amounts of GFO, bio-pellets or carbon can adversely affect corals.
5. Try feeding them at night when you see a feeding response.


Good luck and post an image if the issue continues.

 

This is what i believe corailline was referring to