How to tell if a clam is carrying pinched mantle?

DSC reef · Oct 7, 2019

@OrionN great reads and thank you for the information.

OrionN · Oct 7, 2019

hart24601 said:
It's been interesting to see FWD and PM posts come back now. In the past decade and maybe 60 clams or more during that time I have never had a single specimen that responded well to FW dip but every all online reference I would find pretty much suggested FWD as cure all's. I have had some healthy clams that get ruffled for a few days then are fine too, so I'm glad the discussion is opening to a broader look at various organisms and diseases as for my perspective over dozens and dozens of clams have been that fresh water dips do nothing despite it being in almost every "clam not looking good" thread.

Correct diagnosis is everything.

Once the treatment for PMD disseminated and are well known, almost all clams with PMD was appropriately treated by people dealing with clams. Because of this reason, by the time the clams get to us, they no longer have PMD. There are other infection and illness clams get. Internal infection does not response to FWD. I am sure that was why your clams did not get better with FWD.

As documented in my write up, FWD works very well for PMD.

hart24601 · Oct 7, 2019

OrionN said:
Correct diagnosis is everything.

Once the treatment for PMD disseminated and are well known, almost all clams with PMD was appropriately treated by people dealing with clams. Because of this reason, by the time the clams get to us, they no longer have PMD. There are other infection and illness clams get. Internal infection does not response to FWD. I am sure that was why your clams did not get better with FWD.

As documented in my write up, FWD works very well for PMD.

Very interesting. So pretty much no clams bought from large places should have pmd as fresh water dips have become common among importers? I have seen Dr Mac say they FW dip all clams.

OrionN · Oct 7, 2019

Back in 2002-2004, there were all kinds of discussion regarding treatment for PMD. I estimated that when I advises other reefer on treatment, about 90% of the time it works. I talk to Barry before he sold his business, he used FWD for PMD. Even Dr. Basti and his group who thinks thinks that PMD is cause by internally infected Protozoa recommended FWD as first line treatment. A quote from his article on treatment of PMD is as below. This is really interesting because logically FWD will do nothing to treat the disease if the infection in in the tissue.

"Treatment: fresh water dips
Place the clam in RO water that the temperature is the same as your tank and (ideally) adjust the pH to match that of the aquarium. Move the clam from side to side in the water, and this will help get some of the RO water in between the mantle and shell where the parasite seems to be present.....

Try to place you fresh water dip container under some lights to encourage the clam to open a little. Take a turkey baster and shoot water at wherever the pinch it. You can leave the clam in there for 20-30 minutes. Tridacna crocea may be exposed to even longer periods of immersion, as we found that they tolerate RO dips better than T. maxima. The clam can then be returned to the aquarium.

You may find that this process will have to be repeated several times, but we would suggest waiting a day or so between dips so that the clam can recover from the process."

One can tell that who ever wrote this passage have no experience in keeping clams. A clam that is summered in fresh water will not open just because there is "some light" that is shinning on him through the fresh water.

I have not done a survey on wholesalers regarding whether or not they FWD all their clams. I know that at Tropicorium, Dick Perrrin FWD all his clams on arrival. Maybe we should ask and get an idea of the frequency of FWD the clams get through before they get to our tank.

iandb · Nov 5, 2019

I wanted to revisit this one more time since i want to make sure of a few things. Here is another picture of my derasa that is pictured on the original post (sorry for the dirty glass):

First thing is that from what I understand it is impossible for there to be a clam that is carrying pinched mantle without exhibiting symptoms...Is this correct?

Second thing is even if it was possible for a clam to be a asymptomatic carrier of pm, would a clam be able to grow and appear otherwise healthy?

Lastly I am just looking for final opinions if you guys think there is anything wrong with my derasa...I would like to move it to my bigger tank with my big blue maxima so that the small tank can become quarantine for more clams!

OrionN · Nov 5, 2019

@iandb,
You just got to get better pictures for us to tell if there is any problem. However, gowing clams over 8 months should have no infectious problem. If your clam go downhill now, it is becasue you either exposed it to something, or the condition of your tank change (water chemisty, light or current).
There are many cause for irritated and pinched mantle. PMD is one of these causes. IME, there is no clam that is a carrier of PMD and not show it. I suppose that when the clam just got infected with a few parasite, it may not show any symptom yet. This period only last for a few days at the most. You have a growing clam for 8 months, he is healthy. If there is any disease, It would be from the Maxima that you got 8 days ago (on the day of your original post). I QT my clams for about 1 month before I put them into DT system. I have a 40 gal breeder that I use to QT corals, anemones and clams.
So on your three questions:
1. PMD have no long term asymptomatic phase, maybe for a few day, but not 8 months
2. No. See answer to question number 1
3. I don't think your Derasa have any disease. It is growing well, however, it seem that his mantle is over expanded, which is a sign of perhaps lower light than optimal. If you provide more light, he may do better.

I see that you question the ruffle area on the mantle. I think it is the product of over expanded mantle, nothing more.

iandb · Nov 5, 2019

OrionN said:
@iandb,
You just got to get better pictures for us to tell if there is any problem. However, gowing clams over 8 months should have no infectious problem. If your clam go downhill now, it is becasue you either exposed it to something, or the condition of your tank change (water chemisty, light or current).
There are many cause for irritated and pinched mantle. PMD is one of these causes. IME, there is no clam that is a carrier of PMD and not show it. I suppose that when the clam just got infected with a few parasite, it may not show any symptom yet. This period only last for a few days at the most. You have a growing clam for 8 months, he is healthy. If there is any disease, It would be from the Maxima that you got 8 days ago (on the day of your original post). I QT my clams for about 1 month before I put them into DT system. I have a 40 gal breeder that I use to QT corals, anemones and clams.
So on your three questions:
1. PMD have no long term asymptomatic phase, maybe for a few day, but not 8 months
2. No. See answer to question number 1
3. I don't think your Derasa have any disease. It is growing well, however, it seem that his mantle is over expanded, which is a sign of perhaps lower light than optimal. If you provide more light, he may do better.

I see that you question the ruffle area on the mantle. I think it is the product of over expanded mantle, nothing more.

Thanks for the response! I know the other maxima is not sick as it has been in a different tank from the derasa ever since i got it, and is already growing, with a fully extended mantle covering the entire shell if you look from on top...I did take notice of the over extended mantle...it does not always look like that normally it spreads out more to the side

More pics (they are not the best)

OrionN · Nov 5, 2019

Your Derasa is fine, and healthy. I do know that hey move around some, especially when they are small. I would move him a bit away from the wall. Long term next to the wall may cause deformities in the shell.
Picture of your Maxima please.

iandb · Nov 5, 2019

OrionN said:
Your Derasa is fine, and healthy. I do know that hey move around some, especially when they are small. I would move him a bit away from the wall. Long term next to the wall may cause deformities in the shell.
Picture of your Maxima please.

pic: (those mushrooms and zoas have since been moved...this is a 5 inch maxima):

OrionN · Nov 5, 2019

Just for interest shake, here is (was) a thread on ReefCentral back in 2002 where I advised other reefer on treatment of PMD.

Clams - pinched mantles - Reef Central Online Community

Clams - pinched mantles Tridacnid Clams and other Mollusks

reefcentral.com

Aswswild · Nov 20, 2019

I have question about my clam as well since we are talking about PMD take a look at mine he has these stupid green stars on him an I try to scrub an cut them off but they always come back. Do you think this will lead to anything, they have been there @ a year now.let me know if u want a deferent pic.

Aswswild · Nov 20, 2019

Thank you

OrionN · Nov 20, 2019

Take the clam out and use a sharp point to scrape them off. This will take care of it if you take care and remove the GSP. Better serial pictures needed to determine if a clam has PMD or not. Clear picture of the part of the mantle involved 3-7 consecutive days