Clam QT

[ctenophore]

I want to share this story with everyone to reiterate the importance of quarantine for clams, which is sometimes overlooked. Pyramid snails are a common pest to look for, but they are easy to remove.

 

Perkinsus olseni and/or Perkinsus marinus are shellfish pathogens that are starting to be found on imported Tridacna clams. I haven't run into it yet, but my friend in Gainesville (FL) may have when he picked up a few baby squamosas a few months ago at Macna. These were supposedly aquacultured, and were definitely free of pyramid snails. One by one, they died, despite excellent water quality and targeted feeding (small clams sometimes can't quite get by on light alone). About three weeks ago, one of his oldest Croceas started looking bad, not opening up all the way. Two days later, it was dead. Then over the next two weeks, he proceeded to lose 4 or 5 more clams, including a spectacular 7" purple, blue and gold teardrop maxima which was in captivity for over 6 years. The sole survivor (so far) is a 12" derasa that was taken out once the second or third clam died. Nothing else was affected, all sps, fish everything are perfectly fine. Lesson learned, no more wild clams without a 2 month or more quarantine period. For those of you with prize clams, please think about this before adding any new ones unless you are sure of the source. I am not aware of a means to detect or cure Perkinsus outside of a lab.

 

Here is a quick article from UF describing the problem and the implications for aquaculturists of both ornamental and food clams.

[Coral Hind]

Great info. Thanks for sharing!

[reefhunter]

I just lost my favorite clam... I hope its not b/c of this...

 

BTW... dead clam... by far the worst smelling thing I have encountered....

[jason the filter freak]

Is there a dip that works for this... I don't have facilities to QT clams

[ctenophore]

Is there a dip that works for this... I don't have facilities to QT clams

Not that I know of. This really only pertains to those that have existing healthy clams. If you don't have any, then the first one is essentially in quarantine, since the pathogen doesn't affect anything else.

[ctenophore]

Here's an article I found that hints at successful treatment, maybe someone with access to this journal subscription can get a copy of the entire thing?

 

No idea if this would be safe for Tridacnids though.

[geofloors]

I give my clams a 1 hour freshwater dip. Using RO/DI treated to keep the pH at about 8.2. This will kill any pathogens that might otherwise survive other methods. This will not kill pyrmid snail eggs.

 

 

George

[ctenophore]

From what I have found so far, FW dips may be useful early in an infection cycle, but not so much once infection has progressed. The parasite is systemic, so it would probably take a very long FW dip to get osmotic differences high enough to kill the parasite deep in the host tissue (i.e., long enough to kill the clam). But I'm certainly no marine invertebrate pathologist, so that's total speculation. Here is a discussion on another club message board that has pics of the Perkinsus parasites. Note the thread author's correlation between ferric oxide (GFO/GFH) usage and Perkinsus outbreaks.

[geofloors]

I have done 15 minute FW dip, symptoms come back in a week. 30 minute FW dip, same thing. So actually we were going for a 45 minute dip but forgot about them and now all the clams have been symptom free for many months and growing. I figured I had nothing to loose so we kept going longer and longer. The hour long dip was the cure in my case. That's a long time for any saltwater animal to be in freshwater.

 

 

George