Clam showing no growth

ejmeier

Active member
Hi guys.

I got a 5" Derasa Clam a couple of months ago, and it has been in good apperance/health from day one; mantle extension has always been good. It came to me with a white rim on the end of the shell - showing recent growth.

Yet shortly after adding this clam to my reef, the white rim quickly got covered with coralline algae and stopped growing. There is now no sign of growth in this clam.

The clam is under a 20k 400w MH bulb. He is placed on the bottom of the tank on a CC substrate approximately 21" from the top of the tank.

My Ca is typically between 370-425, with an average value of around 415. Alkalinity is usually between 8 - 12, with about 10.5 being average. PH is around 8.1 - 8.3. Temperature is in the range of 80 - 83 F. SG is kept at 1.025.

I have checked this clam at night and have not found parasitic snails on his mantle, and I have even taken him out of the tank in the middle of the night for a few minutes to inspect the underside of his shell, and have never found any sort of parasites.

The only thing that I will mention is that I do have a neon goby that will sometimes swim into this clam's mantle and irritate it. This is only on an occasional basis, and does not appear to have any lasting impact on the clam.

This is the only clam currently in my tank.

Does anyone have any idea why this clam isn't growing?
 
About 2 years ago I purchased a 4" dereasa from an online vender.It turned out to be a carrier of the dreaded clam disease.Within 3 weeks my 3 maximas and 1 squamosa which were growing nicely were dead.The dereasa never grew in the 2+ years I had it before I parted with it.Just something to think about.What kind of lighting was it under before you got it?I'm no clam expert but maybe the 20k bulbs aren't to it's liking.
 
I have no idea what lighting it was under before I had it. I got it from liveaquaria.com

I also tried a 10k bulb for a few weeks in place of my 20k, but didn't like the coloration in some corals, so I switched back. During this time, the clam didn't act any differently or show signs of growth.

I have been considering disease or some other mysterious thing as to the cause. I have also been considering doing a FW dip, yet I feel it may be too early for anything like this. I mean, sure the clam isn't growing - but it's not dying either. Doesn't seem too urgent, just trying to figure things out...:)
 
I wouldn't clam dip yet. I assume that all other tank parameters are within acceptable ranges, silica, etc.. (alittle phosphate is OK)

I could be completely wrong but I could have swore that clams like derasa will go through growth spurts where the mantle shows growth and it become visible taller. Then it will grow the thickness of the shell during which the mantle will not creat with white. Not 100% sure on this but I do notice that my derasa will grow like a weed for a couple months then slow down for awhile then explode again. Again I could be totally wrong. Have you tried experimenting with the light proximity, (moving it higher in the tank) or shading it for that matter?
 
stiffljp - I thought that clams grow to their full size length-wise, and then following this begin working on shell thickness. Anyway, I'm not 100% sure either, but I've never heard of a clam showing no growth to be a good thing.

I do have a new development though. It seems I am getting closer and closer to doing a FW dip. Just today I am noticing that a few parts of the mantle aren't quite looking like they are supposed to. I wouldn't call it pinching, but more like a "folding" or overlapping of the mantle. This seems kinda weird, and I am getting poised to do a FW dip - its the only thing that I can think of...
 
Is it getting any type of phytoplankton? Do you have a UV or Ozone generator that would prevent phyto from growing in your water?
 
I have been feeding DTs, though I have been slacking off lately, and haven't fed it in about a week or two. I figured since he is a pretty good sized clam, he shouldn't be too dependant on phyto anyways.

I don't have any of those gizmos you mentioned. I do have a decent refugium and snails spawn in my tank a lot - or at least I think so judging by the swarms of Stomatella snails that I now have. :)

BTW - Just looked at him again, and it is now three places in his mantle where it is "folded" slightly.
 
Just an update:

I decided to do a 15 minute FW about a week ago. It took about 3 days for him to fully bounce back from it, but he's back to normal. The folding of the mantle has stopped - at least for now, but he's still not growing.

One other interesting note: I moved him from one side of the aquarium to the other when I was rearranging things, and I noticed the next day a Pyramidellid snail on the glass right where the clam had been. Could it be snails? I have checked several times in the night and haven't seen or found any snails. Can these things live INSIDE the clam? That is the only thing I can think of...
 
The parasitic snails can bury in the substrate. If you have any astrea or trochus snails, check them for pyramids as well.

Good luck
 
remove food, deny them hiding to predators, and manual removal are the only means I am aware of.

FWIW: Barry at clamsdirect had to remove all the sand from his system to get rid of them some time ago. Must have been one heck of a job.

FWIW2: I had a batch of pyramids in my 70 gallon and I removed all the snails and clams that were left and the pyramids apparently died out. It took at least 6 months though, and I do have a 6-line and a tusk fish in that tank.

I would stay with the manual cleaning of the clams and add some predators prior to removing the sand but if you keep finding them a few months from now, I would take the more drastic approach.

A PM to user "zenya" might be a good idea as well, I believe he fought them for awhile.

Good luck.
 
I thought these snails were more specialized predators, and that they only prey on clams. I have never seen any on any of my other astrea or trochus snails... :confused:

It is one thing to simply remove my Derasa (my only clam in the tank), but it is something totally different to remove all my snails, and possibly my substrate (not gonna happen). I have a CC substrate, and I am guessing that they can hide in there. But without the clam, how could they survive?
 
They are predators specializing on mollusks. They will definitely attack the larger snails. I lost about 10 very large and ancient astreas before I figured out the little "babies" were actually feeding on the larger snail.

When the snail is on the glass, you can see them hanging on to the shell around the opening/foot. Keep in mind they can be really small, but will still have a distinct snail shape.

Good luck.
 
It's been a long while since I last updated the status of my clam.

It has still shown no growth after all these months. I have had it under nearly every kind of lighting scheme possible. The clam just appears to be "disturbed". :(

After a few weeks/months, it begins retracting its mantle, and I do a FW dip. This cures it for a while, but it always comes back.

Now I have just decided to let it go and see what happens if I just let everything run its course. Well, things aren't looking good. :( I noticed a new hole on the top of its mantle today. I am getting sick of doing FW dips. Do any of you have any idea as to what could be going on with this clam?

Here's a pic of the clam, it appears healthy in most aspects, except it shows no growth, and the mantle is having some "problems".
 
Eric, leave the poor clam alone. Stop moving it frequently, let it settle. I have 3 clams, two croceas and a maxima. The maxima is restless and frequently laying on its side and I move it a lot in the tank trying to find a suitable place it likes (or I like :) ). The two corceas settled on the rocks nicely and, therefore, left alone. The two croceas have shown amazing shell growth while the maxima never had any. I let the maxima alone (because I am tired of looking for an aesthetically pleasing location for it).Result? The maxima's growth is stunted...here are pics. Note: The croceas shell were smooth when I got them. Those scutes you see are growth from my tank.
Crocea1..
339%3C3%3C5923232%7Ffp58%3Dot%3E232%3B%3D863%3D467%3DXROQDF%3E23234%3B6845744ot1lsi

Crocea2...
339%3C3%3C5923232%7Ffp54%3Dot%3E232%3B%3D863%3D467%3DXROQDF%3E23234%3B6845753ot1lsi

Maxima...
339%3C3%3C5923232%7Ffp54%3Dot%3E232%3B%3D863%3D467%3DXROQDF%3E23234%3B6845763ot1lsi

The maxima is now showing some growth as you can see. The lesson is ...leave it alone.
 
That's what I've been doing for last three months. I haven't done anything to it at all.

Result?

It is doing worse than ever.

During the first few months, it was just irritated at the mantle, and when I got my hands in there and intervened with a FW dip, it recovered.

Now that I have left it alone, it is not only receding at the mantle, a new hole is forming in the top of the mantle. It is doing worse than ever, and will probably die without intervention soon.

I really haven't been moving it around *that* much. I've had it for nearly seven months. It has mainly been in two different tanks, the current one for roughly 3 - 4 months.
 
Clams will divert a significant amount of energy to attachment especially when small. This energy is normally used for growth.
Does it have a substrate to attach to?
I would continue feedings with live phytoplankton and give it a shell or piece of liverock to attach to.
Adam
 
Back
Top