Tridacna Wipeout - Iron Dosing, Disease?

[mpedersen]

OK, guys, I am truly stumped. I asked Barry @ clamsdirect, he is arguably stumped too.

I'm not going to rehash the details here, I hope that you can all accept that I test "EVERYTHING" under the sun when it comes to water quality. Things have been going FINE in this tank. The water is "pristine" and everything has been prospering in this tank, including our Tridacnas.

Back on the 19th & 20th, we lost 2 of our tridacna clams and a flame scallop. This was alarming, they went down "hard and fast"; I did a water test (spotless) and 15% water change. Things looked OK otherwise, except for one Crocea who seemed a bit "unhappy", not fully extending his mantle, perhaps only 75% of his maximum. We had to leave for Xmas vacation for 4 days. Sometime over this trip, the "unhappy" crocea declined fast and died..can't say when; it was found by our "aquarium sitter" a few hours before we returned home.

Since our return, we have lost another crocea, a maxima, a squamosa...the derasa looks like it will be dead by nightfall. In the last 7 days we have lost over 50% of the tridacnids in the tank. EVERYTHING ELSE IS HAPPY (heck, the cardinalfish are breeding).

After reviewing all my notes (I keep a log of EVERYTHING I do), the only thing that I'm kinda leaning towards is the dosing of Iron that I started on December 14th. We're using Kent's Marine Iron at a rate of 1 drop per 5 gallons daily. Prior to and After starting this Iron dosing routine, we have never had ANY detectable levels of Iron / Chelated Iron (via Seachem's Iron Test). Our Macro Algae has seen a "boost" and our second tank which is also now getting iron has had NO problems (however, there are no Tridacnids in that tank).

We've ruled out EVERYTHING (and I mean EVERYTHING) except for the IRON DOSING or DISEASE. I'm hoping maybe someone can rule out the Iron dosing (because they're doing it with the same products at the same rate and have the same undetectable levels WITH TRIDACNAS in their tank). Ruling out Iron would only leave me with Disease...a horrible conclusion that somehow I can "swallow" knowing that I have done EVERYTHING I POSSIBLY CAN DO...at least we can perhaps then try to "treat" this mystery.

I welcome any and all crazy thoughts here.

MP

 

[Anonymous]

I do remember that people where having clams wiped out by introduced disease about 3 or so years ago. I dug up an old thread on it for ya. Although if you talked to Barry I would think he would recognize the clam disease.


http://www.reefs.org/phpBB2/viewtopic.p ... am+disease



I suppose there is also the possibility of some kind of introduced toxin that you can't test for, like some kind of aerosol sprayed in the house, or something on someones hand that went in the tank.

 

[Ben1]

I hate to state the obvious but did you look at night for pyramids? I know you said you ruled out everything but I just wanted to ask....

 

[npaden]

Have you added any other clams recently.

I had a similar experience when I purchased a clam and 3 weeks later the dozen clams that I already had in my tank were dead along with the new clam.

 

[JustForTheHalibut]

Sounds like a possible pathogen since all the chemistry appears to check out fine. I can't imagine we know everything there is to know about clam diseases.......I bet we haven't even scratched the surface. That being said it might be extremely difficult to track down the root cause of this one.

Any newly introduced organisms without quarantine (not just clams)?

 

[mpedersen]

Evening Guys, thanks for all the thoughts and ideas. Gonna try and address them all in one fell swoop.

Laura - I'm apt to eliminate "toxins" for a couple reasons. 1st, a general poison (i.e. cleaning solution, bleach, whatever) would NOT be limited in it's effect to soley the Bivalves in the tank. 2nd, I would expect a more accute response, not one that's drawn out over several days. Finally, the activated carbon (Black Diamond) was replaced 10 days ago...it should still be pretty functional in removing any kind of introduced toxin. The "clam disease"; I believe what you are referring to is probably what Barry's forums refer to as "pinched mantle" or "PM". Yes, a possibility indeed - I honestly don't have enough info to make that diagnosis and even if so, it doesn't look like there's a real treatment for it.

Ben - there are Pyramids in the tank and they have been in there from the get go. They are well controlled (I manually patrol at night once in a while, checking the undersides of all unattached clams in addition to the outer shells, and if a heavy infestation is noticed, I go NUTS to bring it down manually, scrubbing and picking). Here's the kicker; there have always been a few around but through EVERY check I have found NONE, not a single one, present on any of the clams that reside on the rockwork...the Pyramids seem limited to the clams on the sand and again, their numbers are kept in check and remain low. I do beleive that IF there were a disease, the pressence of pyramids in the tank wouldn't be helpful in controlling it's SPREAD.

Npaden - the last addition of clams was on Dec 6th from Barry. He hasn't had any issues reported back from other clients (see my thread under "Clam Emergencies" on his forums). Everything was doing well up until the 19th/20th, then the "2nd round" of deaths which I don't know when it started (as we were out of town) but seems to have ended today, on the 27th. 3/6 clams remain happy "as a clam", the other three look distrurbed but not on death's door. What you experienced DEFINITELY FITS MY TIMELINE! What else can you tell me about your wipeout? Was anything else in the tank affected? Seriously, you summed up in one sentence what it appears I'm going through...ANY INFORMATION could be helpful!

Justforthehalibut - At first and in all my threads I would have answered the "any new animals" question as a no, but I just remembered that our two Captive Bred GreenStriped Gobies are NEWER than the clams....will have to go check the date to see when they went in. Sadly there's no place to set up QT here...trust me I know the risks that come with skipping QT and I may be paying for that circumstance right now. My only weapon has been chosing good reliable suppliers and whenever possible, hand picking my livestock personally.

Please continue to respond...most all of our "irreplaceable" clams have passed EXCEPT our Blue-Spotted Crocea...I'd like to keep him around if possible!

Thanks!

Matt

 

[npaden]

Matt,

Sorry to hear. All of my clams ended up dead so hopefully you will do better than me.

The first clam to die in my tank was the newly introduced one. Is that the same for you? Also the clams in my tank started dieing based on their proximity to the newly added clam. They closer they were, the sooner they died. Maximas seem to me to be the quickest to succumb and then croceas then derasas.

If you have some that are still looking bad, you might do a search on fresh water dipping. Minh Nugyen (not sure if I spelled that right) had a long thread on it several years ago. It seems to work for some and it is better than just watching them die.

Good Luck.

 

[danmhippo]

Matt,

Have you ever tried dissect the near death clam? I did that once out of curiosity when my clams died one by one until the last two. I did find a small pea-shaped and sized crab, totally white, with belly full of eggs.

The mysterious death seemed halted after the removal of that crab.

Some said the pea crab does not harm clams, I am sceptical.

 

[mpedersen]

Wow, now that's interesting. I haven't discected any because, well, I think I'd be passed out on the floor and have treated for toxic vapor exposure...I cannot tell you how badly these things reak when I take them out of the tank, let alone the virtual "bag full" I now have frozen in the freezer. I've never smelled anything like this "frozen" that still stinks up the entire kitchen if I just open the bag long enough to input our latest victim.

UPDATE - in the last 24 hours our last remaining squamosa went from totally happy to dead. Our only remaining tridacna's are the newest Crocea and our Gigas (an older resident). The gigas is probably going down next. I didn't post this last night because I was busy keeping the eagle eye on the tank as the A. margaritophorus went for another round of spawning...they were hot and heavy for 4 hours yet by midnight had still not sealed the deal. Pulled the doa squamosa and turned out the lights...haven't turned them back on today to see if they spawned overnight OR if any more clam demise has occured.

MP

 

[FragMaster]

Matt,
This may have already been asked or you may have already stated it so excuse me if you have or it has.
Was the foot of each clam/scallop intact when you found them?
Was there a noticable hole straighth trough the cam, or scallop leading directly to the foot.
If there was then large bristle worms are you culprit.
THey can and will eat clams and scallops when they get larger.
They start at the foot when they are in the sand, and eat straight through to the top of the mantel and exit through the ventricle above the foot. when there done they leave behind a hollow clam and a straight through hole.

 

[mpedersen]

Fragmaster, I can safely 100% rule out Bristleworms. Anytime I see one I remove it (even though the "small" ones are supposed to pose no problem). Haven't found ANY munching on our clams, ever, even during a nocturnal check. I've seen 2 in our tank since it's setup and both were prompty removed. Both were 1.5" at best.

Also, bristleworms wouldn't suddenly just start wiping out the entire population of clams in a week's timespan after a couple months of no problems, nor would they account for the receeding mantels.

FWIW,

MP

 

[FragMaster]

Have you added any new fish? A cory wrasse for example will pick at the clams mantle.
Other than that I would have to say its a parasitic disease aflicting your clams.

 

[mpedersen]

Nope, there aren't any tankmates that should pose any problems for the Tridacnids - in fact, we set this tank up as a Clam Tank secifically after watching a Coral Beauty and Blue Hep Tang eat/kill some of our earlier clams in our initial tank.

The sad sad news....our gigas croaked (as expected) this evening. At this time the remaining clams (blue spotted crocea and 2 hippopus) look healthy. So we're basically down to 1 Tridacna. I dont' even want to count how many died...it's on the order of "several"...at least a half-grand in clams

Meanwhile everything else is doing A+. Go figure.

MP

 

[Len]

mwp, i had this happen to me too I lost more then half a dozen tridacnas in a span of 72 hours 2-3 years ago. During that time, people were having the same problems and attributed to disease (bacterial or protozoan, i forget). I let the tank be without a clam for 6 months and new clam additions seemed to be not get affected. I'm sorry to hear about your loss, and hopefully my experience sheds a little insight.

 

[mpedersen]

Well Len, I think the plan is to "wait" a while and try again, so your experience and advice is comforting...in the meantime I have PLENTY of other "GOOD" stuff happening in the tank. Granted, Tank #1 is currently "clamless" and has been for a bit...I could always try to appease my clam fix over there

Matt

 

[FragMaster]

Man I am sorry to hear that ! SO much money and so many specimens lost. OUCH!
I hope you get it figured out soon.

 

[mpedersen]

I feel like a sports announcer call the end of a blowout game...and my team is hopelessly losing.

I'm keeping an eye on our last remaining Tridacna, the "newest" crocea, and all day (OK, more specifically this evening) it was outputting mucus off it's mantle again. For the last few hours this evening, before I turned out the lights, it looked to be at only 75% of it's typical mantel extension...not a good sign from what happened with all the others. Remember, this clam DID put down byssal strands and WAS attached within a few days of introduction...only to drop those strands and "detach" earlier thise week. At this rate, I don't expect it to be alive come Sunday if it's now coming down with our unknown plague. The Hippopus seem to be totally "oblivious" (thankfully).

FWIW,

Matt

 

[Len]

A similiarity is my only T.crocea (amongst 5-6 maximas ans 1 squamosa) was the last to die of the group. Maybe T.crocea is more resisitent to this disease.

 

[FragMaster]

Man If I were you I would be doing some SERIOUS water changes, testing for copper again, and making sure your not overdosing anything.

 

[mpedersen]

Quite Possibly Len. This morning the last crocea looks great.... I'm hopeful.

Fragmaster, I'm considering a copper test but it would only be to rule it out and honestly, I think it's beyond a long shot that copper would be to blame. I don't use it (obviously) so the only potential source would be our tapwater. Copper also would have killed a lot more than just the clams.

A lot of us (myself included) will instantly jump to water changes when things go south, but that can sometimes do more harm that good. In general, we do water changes to dilute waste and potentially restore elements lost in the running of the tank. But, water changes are NOT a necessity IF things are properly maintained and levels check out - i.e. I am aware of a shop owner who's running a reef that's currently 14 years WITHOUT A WATER CHANGE and overall, it looks great, everything is in good health (although some of his fish have that "overly old" look to them now).

I did do a 30% water change but the truth is there's no need to keep doing them when the water in the tank tests correctly. Water changes are stressful, so to continue doing them could have made matters worse. Granted, you can't get much worse than losing pretty much every Tridacna, so I guess it might have been worth a shot.

Without having any basis for doing them (i.e. Nitrates were too high, elevated levels of Ammonia or Nitrite that had to be quickly brought under control) I decided that we were better off not adding additional stress and simply trying to "ride it out". I don't think we'll ever know if I made the right or wrong call.

FWIW,

Matt