Mystery derasa clam ailment

[TheWyatt174]

First post! Sorry its not a happy one
I got home today and my clam that I have had for about 5 months now is gaping open wider than I have ever seen it. It also seems to have a bump in the center of the mantle as well. This weekend everything was fine and I even have pictures from then as well for comparison. When I got home it seemed my urchin had dislodged a part of my rock work, but it was only near the clam and not on it. I added new carbon Sunday and that is the only thing I can think of that I have changed physically. My neon goby every so often I have noticed swimming near and perching on the clam. It has also been going underneath the clam and swimming through the gap between it and the clam holder. I looked at the bottom of the clam and I can see very tiny organisms of some sort. They don't look like snails to me but seem almost like a small rectangular adult copepod maybe? I just wanted post something to be extra sure. Its my first clam and it has been doing very well and I would like to keep it that way!!

 

[DSC reef]

Hard to say what's going on, is chemistry stable? The clam looks stressed and I'm not seeing any new white shell growth. Could be from the picture too.

 

[jda]

Has is grown any? This is the only positive sign for a clam. They can look "good" while dying the whole time and it gives the reefer a sense of false-positive.

All of this said, it does not look bad to me.

Let us know how it looks today and if it has grown any.

 

[reef lover]

I looked at the bottom of the clam and I can see very tiny organisms of some sort. They don't look like snails to me but seem almost like a small rectangular adult copepod maybe

Pods arent triangular...sounds like pyramid snails...

 

[OrionN]

I agree that the clam does not looks "good" due to no grow on the shell. Very hard to say what may be wrong.

 

[TheWyatt174]

The bottom picture was 2 days prior to the top photo. Today it seems to be back to normal with mantle extension and no gaping at all. There is a asterina starfish crawling on it near the mantle. It has been growing quite steadily in the past months that I have had it (about 2cm or so radially). Although looking today I don't see a full white growth ring on it, just in some places. You can make out a very small sliver it seems to me but I could be wrong. Also the very small organisms I mentioned are rectangular not triangular like the pest snails normally seen. They definitely crawl unlike a snail.

As for parameters
Salinity is 1.024-1.025
I'm sure if my other tests are reporting accurately or my dosing pumps are messed up because:

Mg is about 1400ppm
Ca does not register so over 500ppm
and KH does not register so over 14 dKH

but if that was the case I would think I would be having a lot more issues in my tank other than my one clam. All of my corals are open and happy fish are acting normal and eating, urchins are bulldozing around holding onto their collections, and even the cleaner clams I have are open and filtering the water. I even saw one of my berghias while testing my water. The kit is a Red Sea combo kit and is less than 6 months old.

 

[DSC reef]

If that's not a testing error then that will definitely cause an issue and the clam could be the first sign of trouble. The clam looked stressed and those numbers can contribute. If those numbers stay that way I would expect some gradual losses. Also, don't lower the alkalinity to fast, make slow changes.

 

[OrionN]

Not registering meaning too low rather than too high?
I end to agree with DSC. Make sure it is not testing error.
Ca and Alkalinity will precipitate out of solution if the product of the two is over a saturation constant, especially when Mg is low at 1440. There is testing error.

 

[OrionN]

On the shell are marks leave by animals that eat hard algae like sea urchin. Not star fish or snails. Chiton and Limpets also do not results in teethmarks like that. Only sea urchin that I know about

 

[jda]

Urchins are semi circular that I can see and mine leave no marks on the shells. Those look like scrape marks from a human tool and could have been there a long time.

Make sure that you do not have Pyramid snails... big time issue. Check the bottom of your clam near the foot to see.