Derasa not opening anymore.

respite

New member
Ive had a 5 inch derasa for a few weeks. Its placed on the rocks, directly under a 175 watt 14k bulb. My halides are 6 inches above the water, and the clam is about 10 inches under the water.

It fully extended its mantle from the day i got it, up until about three days ago. Now its hardly opening, and only extending a small portion of the mantle.

Only fish in the tank is a yellow tang, and a firefish. Ive never seen the tang go anywhere near it. I cant see any signs of nips or tears. I have a few hermits in the tank, but have not seem them bother it either.

Ammonia, nitrates, and nitrites are all 0. Calcium is around 400-420. My ph has been low for a while, it will swing from 7.9 to 8.0 or so. Temp hovers around 80 day and night. There has been no change in my corals or other inverts. Everything else seems fine.

I dont know why its not happy anymore. Should i move it to the bottom of the tank? Let it stay where it is and wait? Move it to someone elses tank?

I much rather get rid of it than watch it die.
 
I'm totally new to this, so I may be talking out of my a**, but don't derasa's like to be on the sand?
 
thats where most people keep them, but they a re fine in the rocks also. clams dont have a brain so they dont know what they like:)
 
Ive never checked my alk. Dont have a test kit so im really not sure. I have checked for snails and other critters on the clam. I even spent some time last night at 3am with a flashlight. Nothing but pods running everywhere.

My bulbs are 11 months old. Its the only thing i can think of that may be the problem.

Like i said, everything else is fine. Its just the clam thats not happy. I dont know, but if the alk is not right, wouldnt it show in my corals or other inverts as well?
 
eric, you need to test you alk regular, any fluctuation could cause this. clams can be pesty at times, did you move it. A sudden change of light may do it.
 
My guess is your yellow tang is skimming mucus off the mantle and causing it to close. You will not see any marks. I am facing same issue I believe.
 
mbbuna, Great post of pics on the killer snails! I had a few around in my last tank, untill, I got a leapord wrase! pyramids do not stand a chance! :thumbsup: ( but now, no small snail stand a chance )
 
<a href=showthread.php?s=&postid=6246165#post6246165 target=_blank>Originally posted</a> by Charlie Davidson
mbbuna, Great post of pics on the killer snails! I had a few around in my last tank, untill, I got a leapord wrase! pyramids do not stand a chance! :thumbsup: ( but now, no small snail stand a chance )

thanks but its not my pic. i stole it from another board just because it is such a good pic of them
 
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