derasa not closing under moonlight

Jadran

Member
Hi

recently I purcehesed hot shot giesemann lamp with computer controled moonlight (260 system). Got bit scared for mine big derasa. Derasa is attached to big piece of LR so I can't replace it. Problem is that during the moon time clam is not closing, it is wide open.. Is this lighting stressing for my clam and is there a risk of killing it?
Lighting is not really heavy, some zoanthids are next to the clam and they are all closed during the moon fases.....

thx. for your reply,


Mario
 
How big is your big Derasa? Derasa do not attach to anything once they get a little larger. Are you sure you got a Derasa? For clams, if you have to move them, just cut the byssal thread. this will not harm them.
My clams do not close at night but do retract their mantels somewhat.
 
Give it some time to acclimate to the change in intensity w/ the moonlights. I suspect it will retract it's mantle to the edge as most do during night.
I don't think this will have an ill effect.
Adam
 
Well it's not really enormous, Id say about 20 cm :o (still my biggest tridacna) yep its derasa
504dermaxy-med.JPG


blue maxy next to it was also open during the night but that one was attached to smaller rock so I removed it and now it is closing during the night..

My clams do not close at night but do retract their mantels somewhat.

do you also have some night light above your tank or is it in complete darkness?

Adam, thx. for the tip I'll let it be for some time
 
Just as Minh Nguyen said. My clams do not fully close at night either, whether in total darkness or a one watt LED moonlight.
The shell halves are not as open, about 3/4" to 1" and the mantle is retracted.
 
My clams are always open. I don't think the clam closing at night is a good thing :P They won't fully close unless something is stressing them out.
 
There is a 5 W night light for my 450 g tank. Only enough light to barely see shape of rock and fish. My clams never close. My 4 inches maxima shell open by about 1 inches or so. Mantels retracted to or just over the shell. This, IME, is normal. I have seen this since 1997 when I start to keep clams.
Minh
 
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