Clam half open

[Jtwinn26]

Have had the clam on the left for a few months now and has grown a full set of scutes. But all of a sudden has only been open halfway for the past four days. Any ideas?

 

[Jtwinn26]

no changes recently. Other clam seems happy

 

[minus9]

Did you just add the other clam?

 

[Tcook]

What fish do you have? Did you check for any pyramid snails?

 

[Jtwinn26]

The clam on the right is new but these symptoms started a day or so before the new clam. No pyramid snails. Blue tang, blue jaw trigger, maroon clown. None of the fish have ever paid attention to any of the clams.

 

[minus9]

Did you pick up the clam to inspect the underside? Look for aiptasia or hydroids next to the mantle. Any parameter swings? Temp? Salinity? Any changes in lighting? Anything else new to the tank?

 

[Jtwinn26]

Gave all the clams a full inspection. Parameters all unchanged for weeks.

 

[Jtwinn26]

Sometimes looks better sometimes looks worse. Was growing a lot and then all of a sudden started behaving this way.

 

[minus9]

Gave all the clams a full inspection. Parameters all unchanged for weeks.

Which are?

 

[Jtwinn26]

1.025 salinity.
78 temp.
9 alkalinity
450 calcium
450 mag
Nitrates 10
Phosphate 0.02

 

[minus9]

Sometimes looks better sometimes looks worse. Was growing a lot and then all of a sudden started behaving this way.

What's on the back side of the clam? Coral? Also, what light level is it under (micro moles?) and how much time?

 

[Jtwinn26]

Red Sea reeder 300xl with three AI prime 16s for light. About an 10 lights on time with dimming up and down at beginning and end. About a 2inch margin of space between him and some clove polyps and mushrooms.

 

[minus9]

Red Sea reeder 300xl with three AI prime 16s for light. About an 10 lights on time with dimming up and down at beginning and end. About a 2inch margin of space between him and some clove polyps and mushrooms.

Thanks! I know you said there's new shell growth, which is good, but it seems to be in very low light to me. I wouldn't purposefully keep clams in low light and for squamosa and derasa, I would shoot for 200+ micro moles for at least 8hrs a day to keep them happy and healthy. My guess is that you're not getting anywhere near that at the bottom of your tank?
Long term, I think you're going to need more light with these guys and I would shoot for 35ppt salinity and about 0.05ppm or more of PO4 to keep everything happy.

 

[Jtwinn26]

I was thinking of adding T5. Any ideas for good add on fixture?

 

[Manny’s Reef]

Thanks! I know you said there's new shell growth, which is good, but it seems to be in very low light to me. I wouldn't purposefully keep clams in low light and for squamosa and derasa, I would shoot for 200+ micro moles for at least 8hrs a day to keep them happy and healthy. My guess is that you're not getting anywhere near that at the bottom of your tank?
Long term, I think you're going to need more light with these guys and I would shoot for 35ppt salinity and about 0.05ppm or more of PO4 to keep everything happy.

This isn't necessarily true. I think the OP has plenty of light for these clams. I've kept a derasa long-term with nothing but natural light coming in from being next to the window. Sure, it was more brown than what we see now days with LEDs but that clam was a healthy thriving species.

To OP, I can tell you from personal experience that your issue is not a lack of lighting.

 

[minus9]

I was thinking of adding T5. Any ideas for good add on fixture?

I think the Aquatic Life hybrid is the way to go with adding T5's. Or just go with stronger LED's if the budget allows? All depends on what you want to keep?

 

[Jtwinn26]

What about this as a little add on?

 

[Mr. Mojo Rising]

I don't see any white at the top of the shell, it has not been growing. My clam always has a few millimeters of noticeable pearly white at the top of the shell.

Do you know the par where it sits? I'm not so sure an AI16 at 24" depth is strong enough for a clam....

 

[minus9]

I'm not sure about those fixtures? Some of those cheaper fixtures might not do well in marine environments? Do you have a par meter or can you borrow one? I think knowing what your levels are will help in the long run.
There are a couple things that can cause a clam to do this and this isn't a definitive list either. Change of flow, pests and/or corals bothering the mantle, pathogens, weakness, etc...

 

[Jtwinn26]

No par meter. Wish I knew someone I could borrow from.