one of 2 clams not opening as much as the other

[O'Man]

Have a dersa and a maxima. Dersa is open wide, maxima is not, though it is not closed. Here's what I am wondering... The dersa is in a "quiet" part of the tank. The maxima is in a "busy" spot. Busy means lots of fish traffic swimming overhead.

Could this be the cause? I really do not want to rearrange stuff, but I do not want to lose the clam. Grateful for comments.
Thanks

 

[toptank]

Can you re-locate the clam to a less active place in your tank?

Barry

 

[O'Man]

I am thinking I have to, but I thought I had everything all set... It will take some creativity.

Thanks,
Brian

 

[kevinpo]

IME T. deresa and T. maxima open different as they have different mantles and T. deresa opens wider. IMO I would not worry about it unless the mantle does not extend beyond the lip of the shell. If you cannot see the edge of the shell I would take no action. If you can see the growing edge all day then it could be a number of things
too much light (yes it's possible)
too much water flow
fish cleaning the shell
fish nipping the mantle

HTH,
Kevin
PS: Barry help me here there must be some other reasons (I've only had 1 cup of coffee so far

 

[jim norris]

O'man,
Are the clams new? What type of fish do you have?
Jim

 

[toptank]

Kevin,

You hit most of what I would also say. It could be that the Maxima isn't use to the busy traffic yet.

How big is that Maxima? Small Derasa will normally open up wider than a small Maxima IME.You can give it a day or so then if he is still reacting by retracting and closing all the time, then I would consider moving him. IMO.

Barry

 

[O'Man]

Fairly new, I would say about 4 weeks. Dersa is about 3-3.25" at the widest part of the shell. Maxima is about 4-4.25". Oddly enough, the dersa was the more closed of the 2 for its first 10 days, now it's nice and wide...even seems to be becoming slightly blue in color.

Maxima, before the lights are on, and the fish are more active, has its mantle fully extended. Throught the day, I can see it retract when the activity overhead is greatest, but it opens back up. Yet by the end of the day, the mantle is much more retracted.

As for seeing the edge of the shell, that seems to happen late in the day. Both clams are firmly attached to the rocks I set them on. Both rocks are sitting right on the 4.5"- 5" sand bed. Tank is a 90 gallon with 7 four foot 110 watt vho bulbs. I am also going to try to evaluate the strength of the current, but both clams are within 3 - 4 inches of one another.

Fish are a chevron tang, orchid dottyback, marine betta & a bluespot jawfish.

Clams are new to me, I figured it was time for me to boldy go where I haven't been before

Thanks again,
Brian