Advice Needed - Odd Tank Happenings

[VA_Reefer]

So just last night I was remarking to my son how great everything in our tank was looking. We have a 34g Red Sea Max that we have heavily modded to include MH and actinic lighting. After a 6 week break-in period with the new lights everything has really perked up and is doing great. Corals growing and really coloring up.

 

I had added a purple tipped anemone a few weeks ago and just last week added a small maxima clam. Both looked great yesterday. The nem was very colorful and had expanded to become very large. In fact, I was starting to worry that maybe it was too large. The clam was well situated and very happy.

 

Last night I noticed that our clowns had finally taken to the anemone and one was hosting it after the lights went out.

 

This morning I came down and immediately noticed the anemone was gone. It was 6-8 inches in diameter when open so it was obvious that it was missing. As I started looking around I saw that the clam had been completely eaten. Nothing left but empty shell.

 

I finally found the anemone on the backside of the rocks that it had been attached to. It's in a bad spot that's difficult to get to. At least it wasn't dead.

 

I'm wondering two things. What in the heck is in my tank that would have eaten that clam? And could that have caused the anemone to move? The nem and clam weren't side by side, but probably 8 inches apart.

 

I do suspect that I have a large bristle worm. Could that have killed the clam?

 

Thanks,

 

greg

[RudyCDX1]

It was the Bristle Worm that got the clam. I have seen it happen.

[ctenophore]

I doubt it was a bristle worm, unless you have a very large fireworm and a small clam. The common pink bristleworms are scavengers, not predators. Typically when a bristleworm is seen feeding on a clam (even though the clam is still open), the clam is already dying or dead. What other fish do you have besides the clowns?

[OUsnakebyte]

I doubt it was a bristle worm, unless you have a very large fireworm and a small clam. The common pink bristleworms are scavengers, not predators. Typically when a bristleworm is seen feeding on a clam (even though the clam is still open), the clam is already dying or dead. What other fish do you have besides the clowns?

I second this, as bristle worms often get a bad reputation for stuff like this. Not that it *couldn't* happen, but unlikely.

[zygote2k]

It's like saying those vultures killed that deer that they are eating.

[lanman]

Clams die... I have limited experience, but from that experience, until a clam has been happily situated for several months - it might be dying, and you don't even know it. Then one day POOF, it's dead. Clams are not recommended for any but very 'experienced' tanks, for what appears to be a good reason. As far as the anemone - he probably ran off because he was getting really annoyed by some clownfish!

 

bob

[ctenophore]

If it was a wild collected clam, there is a chance it was collected improperly, i.e., byssal gland tear. This happens when a clam is pulled from a substrate, causing the byssal threads that hold it in place to remain attached to the rock, and pulling/tearing the gland that produces the threads from inside the clam. The clam can take upwards of weeks to months to die, and it will remain open for most of that. I used to have terrible luck with clams back in the early 90s as this was a common practice and nobody knew what was going on. We all thought bristle worms were eating them.

 

The proper way to remove a clam that has stuck itself to a rock is to get a razor underneath and cut the byssal threads. This goes for divers as well as aquarists trying to relocate a clam in their tank.

[Origami]

If it was a wild collected clam, there is a chance it was collected improperly, i.e., byssal gland tear. This happens when a clam is pulled from a substrate, causing the byssal threads that hold it in place to remain attached to the rock, and pulling/tearing the gland that produces the threads from inside the clam. The clam can take upwards of weeks to months to die, and it will remain open for most of that. I used to have terrible luck with clams back in the early 90s as this was a common practice and nobody knew what was going on. We all thought bristle worms were eating them.

 

The proper way to remove a clam that has stuck itself to a rock is to get a razor underneath and cut the byssal threads. This goes for divers as well as aquarists trying to relocate a clam in their tank.

 

+1

 

I was reading Daniel Knop's Giant Clams book last night and I think this scenario, or a bacterial infection through the byssal gland are your most likely culprits for sudden death and disintegration. If you inspect the shell, do you notice anything odd about the inside surface such as discoloration or small holes? These can indicate some sort of parasite as well.

[davelin315]

I will 3rd (4th? 5th?) that it probably was not a bristle worm. What did the clam look like before it died? Tridacnids show a lot of warning signs before they go south, but unless you know what to look for, you may not notice it and may just think it's a healthy clam. Another thing about clams, once they die, their bodies no longer have all of the water in their oral cavity and so they shrink down to almost nothing and then get eaten. It would be rare for a clam in a reef tank that has any sort of clean up crew or inhabitants to die and still have anything left after a few hours, unless it's simply a really big clam.

 

As far as the anemone, they will often choose a spot that is conducive to what they want. If it is still sticky, then it's always got a chance as the nematocysts are still working. What kind is yours? When you say purple tips, I think of a Condylactus which is not the best for hosting a clown (they will host in them, but they also will sting the clown as it's not really a natural host for many clowns). Perhaps it's getting annoyed with the clowns and retreated to the back.

[RudyCDX1]

Thanks for the clarification on the worm and clam. I actually called a fellow member to discuss an problem with my clam and that is one thing that came up. When looking at it with a flashlight at night it was being eaten by a large bristle worm. The vulture/deer makes sense. I guess that really proves the power of the forum for information.

[VA_Reefer]

Well, I'm no expert but the clam looked to be in excellent health the day before it was eaten. It was a small clam, maybe two inches, but for the most part the mantle was full, extended and very colorful almost always. I could be wrong but I really doubt the clam just died and got eaten as part of normal clean up crew.

 

As for other livestock, we have the 2 clowns, mystery wrasse, and a couple of small gobies. Also a cleaner shrimp, a couple of mithrax crabs, pom-pom crab and your standard assortment of hermits and snails.

 

The thing that concerns me about the bristle worm is that I have the suspicion that it's quite large. I think it's been in the tank for 1.5-2 years. At minimum it's about 8 inches long and I suspect it may actually be over 12 inches long, which is quite large for this size tank. I say maybe because I've never seen the full thing. Just seen it extended out of the rocks, and I have seen it extended 6-8 inches out of the rocks across the sandbed.

 

I wonder if it's possible I've picked up some kind of pest crab?

 

As for the anemone - it's fine - maybe the clowns irritated it. It's relocated to the other side of the tank.

 

Thanks for all the quick replies.

 

greg

[davelin315]

Well, I'm no expert but the clam looked to be in excellent health the day before it was eaten. It was a small clam, maybe two inches, but for the most part the mantle was full, extended and very colorful almost always. I could be wrong but I really doubt the clam just died and got eaten as part of normal clean up crew.

 

As for other livestock, we have the 2 clowns, mystery wrasse, and a couple of small gobies. Also a cleaner shrimp, a couple of mithrax crabs, pom-pom crab and your standard assortment of hermits and snails.

I'm going to take a guess here and blame the hermits and mithrax crabs. All mithrax and hermit crabs are not created equally. Also, the cleaner shrimp can sometimes bother a clam to death. These all could have led to the death of your clam.

 

Another thing is that if it's under 2", it may not be photosynthetic and may be relying only on filter feeding to get the bulk of its nutrition. Depending on the type of clam, they don't begin to rely on photosynthesis for the bulk of their nutrition until they attain a certain size.

 

Also, can you describe "excellent health"? One thing that I've noticed over the years is that people who haven't kept a lot of clams sometimes associate danger signs in clams with good health (much of this was caused by misinformation in the stores they got them from - none of the ones in this area that I have bought clams from have suffered from ill health, although a mail order clam I got did). Gaping of the incurrent siphon and over extension of the mantle are easily confused with a healthy clam in many instances, but are actually signs of distress and in a clam as small as you're talking, recovery is difficult.

 

As far as the bristle worm, it is a large one, but that size is not uncommon. I've got many in my system that are probably upwards of 1'.

[ctenophore]

All good points by Dave.

 

Possibilities:

1) Clam is immature. It's very possible it was slowly dying due to not meeting energy budget- then the other day, it collapsed and the crabs moved in.

 

2) Oddball worm 12"+, which may be a clam/snail predator (Oenone sp? see http://reefkeeping.com/issues/2003-04/rs/index.php)

 

3) Mythrax/hermit crabs, my guess is you may have a hidden "hairy gorilla" crab, these guys will eat anything they can get in their claws.

 

Since you only had the clam for a week and it is likely an aquacultured baby, my guess is #1 followed by crab/worm scavenger crew. Those small clams are touchy for exactly the reasons Dave mentioned. Larger clams are much hardier as they can rely more on photosynthesis for energy.

[Jan]

Well, I'm no expert but the clam looked to be in excellent health the day before it was eaten. It was a small clam, maybe two inches, but for the most part the mantle was full, extended and very colorful almost always. I could be wrong but I really doubt the clam just died and got eaten as part of normal clean up crew.

 

As for other livestock, we have the 2 clowns, mystery wrasse, and a couple of small gobies. Also a cleaner shrimp, a couple of mithrax crabs, pom-pom crab and your standard assortment of hermits and snails.

 

The thing that concerns me about the bristle worm is that I have the suspicion that it's quite large. I think it's been in the tank for 1.5-2 years. At minimum it's about 8 inches long and I suspect it may actually be over 12 inches long, which is quite large for this size tank. I say maybe because I've never seen the full thing. Just seen it extended out of the rocks, and I have seen it extended 6-8 inches out of the rocks across the sandbed.

 

I wonder if it's possible I've picked up some kind of pest crab?

 

As for the anemone - it's fine - maybe the clowns irritated it. It's relocated to the other side of the tank.

 

Thanks for all the quick replies.

 

greg

Edited December 21, 2009 by Jan

[Jan]

This should have been a solo post. Not replying to anyone but the poster...

 

I'm really sorry your clam died. The really small clams, 1.5-2" have a very poor survival rate. Anyone who owns a clam should also own "Giant Clams in the Sea and the Aquarium" by James Fatherree. This book is a must have for any clam owner. BRK has the book.

 

Something doesn't sound right. Full even mantle extension and good color are signs of a healthy clam. It's when you start seeing things like wide open inhalent siphon with no mantle extension, all or part of the mantle folded or not extended (pinched mantle). The clam does not react to light (when you pass your hand over it to cover the light it does not react), white spots (bleaching), etc. Then there's a problem. Clams may also come to you with predators like pyramid snails that slowly eat away at them. They attach at the base and eat away at the clam sucking the life out of them. The other thing that may kill a clam rapidly is tearing the byssal gland. Could the clam have been anchored by it's byssal gland and then been moved causing the gland to rip? They don't often survive this type of injury.

 

The owner of clams direct has a great site with loads of information about clams www.reefaquariumforum.com.

Edited December 21, 2009 by Jan

[VA_Reefer]

Thanks for the response Jan. The clam didn't exhibit any of the signs of distress you describe. It was extended, colorful and exhibited no signs of gaping.

 

I did examine the byssal gland prior to purchase and didn't see any obvious signs of abuse, but of course recognize I could be wrong.

 

I purchased the clam from Marine Scene and felt it was in good health when I got it. I didn't notice any decline after acclimation. It had been in my tank about a week.

 

I'm really suspicious of a predator. I have noticed a few dead snails on occasion recently which is perhaps why I'm a little more suspicious.

 

Thanks for all the great advice everyone.

 

greg

 

 

 

This should have been a solo post. Not replying to anyone but the poster...

 

I'm really sorry your clam died. The really small clams, 1.5-2" have a very poor survival rate. Anyone who owns a clam should also own "Giant Clams in the Sea and the Aquarium" by James Fatherree. This book is a must have for any clam owner. BRK has the book.

 

Something doesn't sound right. Full even mantle extension and good color are signs of a healthy clam. It's when you start seeing things like wide open inhalent siphon with no mantle extension, all or part of the mantle folded or not extended (pinched mantle). The clam does not react to light (when you pass your hand over it to cover the light it does not react), white spots (bleaching), etc. Then there's a problem. Clams may also come to you with predators like pyramid snails that slowly eat away at them. They attach at the base and eat away at the clam sucking the life out of them. The other thing that may kill a clam rapidly is tearing the byssal gland. Could the clam have been anchored by it's byssal gland and then been moved causing the gland to rip? They don't often survive this type of injury.

 

The owner of clams direct has a great site with loads of information about clams www.reefaquariumforum.com.

[Jan]

Greg,

In Fatherrees book he states that bristle worms and fire worms (rare in our tanks) have only been known to prey on sick or dying clams as do crabs and other cleaners. They're cleaners and also opportunistic feeders. He also notes that he has never had success with the smaller, 1.5"-2", clams for whatever reason. I'm thinking it could have been pyramidal snails that weakend your clam. Pyramidla snails are very tiny. About the size of a grain of rice. They're also white which makes them diffficult to seperate from sand or crushed coral. Was the shell intact? Mantis shrimp and the like usually break the shells to get to the fleshy part. Once in the tank pyramidal snails are almost impossible to get rid of. Inspect the shell well.

 

Pyramid snails may also be parasitic to snails. See here:

http://www.wetwebmedia.com/snaildisfaqs.htm

http://www.wetwebmedia.com/MolluscPIX/Gast...ails_id_wwm.jpg

 

This is what you want to look for.

http://www.reefaquariumforum.com/my-pyrami...k-t5012-60.html

 

Edited December 21, 2009 by Jan

[VA_Reefer]

Jan - thanks for the great info. I'll keep an eye out for those.

 

The shell was indeed intact. I still have it.

 

I understand the smaller clams are more difficult to maintain due to the fact they are not big enough to be fully photosynthetic.

 

greg

Edited December 21, 2009 by VA_Reefer

[davelin315]

I have pyramid snails in my system and yes, they are very difficult to get rid of!

 

Mine, however, prey more upon snails and I have yet to ever see one on a clam in my system. If you have them, they'll come out of the sand at night as well. One way to see if you have them is to scoop up your sand and filter it through a fine cloth (if you have sand, that is). The snails are larger than sugar sized grains and will come out as you sift. If you have larger grain size, take some out and stir it around and see if they come out, or just scoop up some substrate and put in a piece of clam to see if they come out.