Do some clams open more?

[Phantom Phish]

I have two clams. A squamosa thats about 4.5 inches, that I've had for about 3 months (and its already added a whole new row of scutes), and a new 3.5 inch maxima that I got about a week ago.

I've noticed that the maxima doesn't open up as widely as the squamosa, which extends its mantle so much that it almost looks like its spilling out of its shell. The maxima opens up pretty well, just not as much as the squamosa.

Lighting is two 250 watt Iwasakis with 3 vho actinics, over a 105 gallon tank thats about 24 inches to the sand bed. Both clams are on the sand.

Is this just a characteristic of the clams, do squamosas open up more than maximas? Or should I think about moving the maxima to give it more light? Any thoughts would be appreciated.

[aliendomain]

Phantom,

Your maxima could be kept on the rock work, but it's up to you, with the 250s the clam will get enough light on the sand bed. It is good practice to put something under the clam like a scallop shell for it to attach to.

As for how far the mantle is extending, a Maxima should extend well over its shell but may not look as large as a Squamosa. The other factor is that your Maxima is still new to the tank, so it could be adjusting still to things like light, current and chemistry. If you can post a photo, I will tell you if the clam is open all the way.

Hope this helps,

AlienDomain

[Phantom Phish]

Thanks for the advice, alien. Can't post a picture, don't have a digital camera yet (keep meaning to buy one, but I seem to spend all my money on corals and clams). The maxima does seem to be opening up a little more today.

I've seen people put a scallop shell under their clams. Is that just to protect them from nasty things in the sand?

[aliendomain]

It gives the clam something to attach to with the byssal threads. And yes, this helps the clam if something were to try to attack a clam via the byssal opening.