clam trouble
 

my 5" clam (cant remember what kind it is) has been partly closed up for the past 3 days. ive never seen any one nip at it so i doubt its that. all parameters are good except PO4 at 2.5ppm + eeeekkkk not unheard of it was for probably a good month or more after we got it so that as well could be ruled out.

I wouldn't put it past the cleaner wrasse to nip at it

It looks like a Squamosa to me. Cleaner wrasse are often reported to pick on clam mantels. To rule that out completely you could isolate the two. Either place them in different tanks or build a cage around the clam. Have you checked the underside of it? My Squamosa was recently being bothered by a large number of bristle worms hiding underneath. Once most of the worms were removed it imediately went back to looking normal. I've also had clams pinch up like that when they were being attacked by pyram snails. Or it could be 'pinched mantel', a condition (pathogen?) that is often curable with a fresh water dip.

If you list things like your tank equipment, other inhabitants and all of your water chemistry parameters that often helps us troubleshoot.

parameters are:
temp 81
salinity 1.021
no3- 1
NO2- 0
NH3 -0
CA2+ - 486
ALK - 142
PO4 - 2.5
MG - unknown

lighting i s3x400w MH@14000k (old bulbs)
tank is 175g bow front
clam is on sand bed
checked yesterday for bristle worms few - removed
something odd foot was not deployed
tank mates:
powder blue tang
one spot foxface
copper band
1-2 chromis
clown
several shrimps

looked up pyramid snails haven't seen any

how old is the tank?

established about for 4 years ago has been moved 3 times since then latest was in january

Your salinity is pretty low for a reef tank. Aim for 1.025 but go slow when raising it.
81F is warm but not too warm, however most people try to be around 78F.
Copperbanded butterflys are also notorious clam mantle nippers. It took a couple of years but eventually mine started doing it. Hell I've even witnessed my powder blue tang nip at a clam's mantle because it didn't like where I placed it in my tank. My tang has issues. And yes I am crazy too but thats besides the point.
What units is your Alk in? 142 doesn't make sense for dkh or meq/l.

142 would be ppm. Which is 8 dkh

Chances are its the Cbb or cleaner

I found that feed the Cbb mussels every couple days kept it clear of clams but forget for a few days and they will nip. I found more so with new clam additions

yeah alk is in ppm hanna readout

should i be doing a fresh water dip