Possessed Rock? No, clam! -- 10/28/2009 Good Morning WWM Crew! <Morning Liz! JustinN here with you, from South Texas!> I hope today finds you all well. We're having a wonderful sunny day here in C. Texas after some much needed rain (droughts are really no fun). <Indeed... but this brisk cool that came along with the rain is sure nice!> I have another questions for y'all (didn't see that coming, now did ya?). <*GASP* I never!> I purchased a lovely green Ricordea from a fellow reef club member a few weeks ago that was mounted on what seemed to be an ordinary hunk of rubble. All appears standard... Ricordea foot firmly attached to the outside of a chunk of rubble that's approx 1" long and about 1/2" wide. After a few days I noticed the bottom section of the chunk of rubble would open up! If the rock was tapped it would quickly snap shut. Being new to salt water aquarium keeping I don't know if this is the Ricordea or something else living in the rock. I searched all over the website and haven't found anything that talks about mounting rocks mysteriously opening and closing. I've never seen anything come out of the rock when it's open. There are no protrusions or any other signs that the rock is anything but a single rock when it's closed. The Ricordeas foot doesn't appear to go down into the rock, but I suppose a central portion of it could extend down through a hole that can't be seen... <Indeed, I see what you are speaking of here -- and this is simply a relatively common filter-feeding clam. You will find them surprisingly abundant in live rock, though you won't often notice them till you see the 'flick' of them closing up. Nothing to worry about, just another of the fun little hitchhikers that come with this hobby.> I've attached a couple (slightly blurry, sorry) pictures that illustrate the issue clearly even if their overall quality is a little lacking. <Adequate enough for identification, yes -- quite a lovely Ricordea as well!> If this is just what Ricordea do feel free to chuckle at me (haha, silly newbies... someday I'll be looking back and laughing at myself so it's all good). If not, then what's up here? Do I call in an exorcist or enjoy an unexpected hitchhiker (umm, and what might it be?)? <Just sit back and enjoy -- and expect to see some more things that'll have you scratching your head!> Thanks so much and y'all keep up the *GREAT* work! Liz <Glad to be of assistance, Liz! Let us know if you have any more questions! -JustinN>

Re: Possessed Rock? No, clam! -- 10/28/2009 Hi Justin, <Liz> Neat that you are in Texas as well. And yep, the cool weather is wonderful. We have to enjoy it while it lasts. <Indeed! It will, of course, be gone all too soon... but that's the price we pay living here!> How awesome! A clam! My boys are ecstatic. We've been having so much fun watching things come alive in our tank. We just got our fuge & sump running (10 gal dedicated fuge, 20 gal sump for our 125 gal tank) and it's amazing all the living things we're seeing. <Ah yes, and this will only increase as time goes on! The wife and I have as much fun watching the emerging critters from our tanks as we do any of our intentionally placed inhabitants -- the variety of life really is astounding!> Thank you very much for helping solve the mystery. :) The WWM site is truly an amazing resource. Y'all do aquatic hobbyists such a wonderful service. Liz <Glad to help! -JustinN>

Can You Identify These Creatures in My Refugium? Harmless Bivalves – 10/22/09 Hi, <Hello, Lynn here today.> ..recently I noticed some creatures in my 30 gal refugium. Can you identify them? <No worries, they’re harmless, filter-feeding bivalves. For more information on these neat little creatures, please see the following links (as well as the related links at the top of each page): http://www.wetwebmedia.com/bivalvia.htm http://www.wetwebmedia.com/bividfaqs.htm > Pics are below: Thank you <You’re very welcome. Take care, LynnZ>

Mystery Bivalve: Likely Mussel – 8/6/09 Greetings Bob & Crew! <Greetings Ray!> I just recently moved my tank <You have my sympathies!> ..and in placing the 50 or so pounds of live rocks (you can never get them the same twice in a row), <Too true> I noticed some sort of bivalve. Never seen it before. Looks harmless enough and I have searched and it is the only one that I can see. This is perhaps the ONLY thing that I like about moving is that I tend to find new stuff every time, <There’s always a silver lining somewhere!> ..even though I have not added anything in a very long time. I tried doing some searches, but have come up empty handed. The local reef club members are also scratching their head. Looks just like a Zebra mussel (now being in the Great Lakes area), but I am pretty sure they are strictly freshwater. <Yes, Dreissena polymorpha (family Dreissenidae), is an invasive, strictly freshwater species.> Any ideas? <It does appear to be very mussel-like in appearance but ID beyond that would require more information: locale of origin, size, views of the exterior - taken from the sides/ends, as well as both valve halves, and optimally, several of the shell’s empty interior – particularly the hinge area. Unfortunately, the only way you’d really be able to get those photos would be to remove and kill the animal, which would literally be overkill. Suffice it to say, this is a neat, harmless, little mussel-like bivalve that makes for a nice addition to your system.> Safe to have? <Yes, no worries with this little guy.> Looks like it is getting along with its neighbors just fine so I would hate to have to pull it out if I don't have to. <I’d leave and enjoy.> Pic attached. <Thanks> Thanks! <You’re very welcome!> -Ray <Take care, LynnZ>

A Mytilid of some sort. RMF

LR Hitchhiker - 02/13/2006
Hello! I've been a saltwater hobbyist for just a few months now and couple of months ago bought my tank red kelp on a piece of live rock. Recently I adjusted it to where there was a little bit more of the live rock facing me, and a couple of weeks after I noticed (what from all my Internet research), looks like two fan worms growing from it, and what looks like a clam?
<Have to love those freebies!>
After two months of being unfed can this be true, can it survive and if it is what can I do for it?
<It could in fact be a bivalve of some sort, living off what it can filter from your water. Can also be the remains of what had been a bivalve (more often the case). Try to establish for certain that it is alive before you worry yourself about it (at night with a flashlight is easiest). Most likely, you will only need to maintain optimal water quality, let it filter feed for itself. Look here  http://www.wetwebmedia.com/bivalvia.htm for a possible ID. - Josh>

Mystery Critter ID What's up Crew!<<  Just typing away. >> I found this critter clamped onto my Hammer Coral's skeleton.  It took mucho strength to pry it off.  It opens up split from the middle and sticks out a pinkish tongue-like flesh. << Haven't seen the pic yet, but already sounding like a bivalve mollusk. >> It's pretty alien looking IMO.  I'm attaching two photos top and side views.  Really appreciate if you can help me ID it and let me know if it is predatory towards any of my corals or inverts. << Well it appears to be some sort of Bivalve.  Looks cool.  Unfortunately with about 14,000 species of Bivalves, I don't think I can be much more descriptive.  I'll bet it isn't predatory and is a great addition to your tank.  This type of biodiversity is exactly what you want in a reef tank, so I say keep it.  Please continue to watch it, and if it on a coral let us know.  Otherwise keep it growing (it needs live rock, and that's about it) and please take pictures again.  Looks pretty cool, and I'm sorry I can't identify it. >> Thanks a bunch! Roy <<  Adam Blundell  >>

What is it?
Hello; How are you?
<hungry and sleepy but still happy. Thanks for asking... I hope you are well too:) >
I was wondering if you could help me identify something on my live rock. 
<I can and will or I'll make up something very convincing>
I have a 29 gallon tank, with 25 lbs of live rock. It is hard to describe in words but I will try. Last night, my emerald crab was eating stuff off the top of one of the live rocks. As I watched him move around, he touched the top most part of the rock with his claw. (it is kind of a pointed section on top of the rock.) When he touched this part, it sank down into the rest of the rock. When this happened,
it scared him, and he ran down off the rock. After about a minute the pointed section rose back up to where it was before he touched it. Is this some type of bi-valve such as a clam or oyster. 
<Where is the rock from? If Atlantic, reference the Turkey Wing (Arca zebra) ... quite common>
It just looks like the rest of the rock to me, and I had no idea there was something living there. After searching my tank, I found a couple other places where the rock is moving. (I guess another reason to call it live rock!!!)
<bingo... hand that man a stinky Kewpie doll>
If they are bi-valves, will they survive by adding phyto plankton to the water?
<yes... but bottled phyto must be whisked in a blender before every use to reduce particle size or it is hardly useful. Hmmm... don't read that on all the bottles do you :) Research shows...>
Thanks for all your help (both now and my past questions), Kevin
<best regards, Anthony>

Re: Arca zebra
Thanks Anthony, on the speedy reply.
<my great pleasure>
What you wrote was right along my thinking. 
<are you sure that you just aren't feeling gassy instead?>
These guys really aren't going to like burst of water from a turkey baster. They close up when a shadow passes. 
<exactly>
Not that I blame them.
<yep... the shadow or unnatural and "large" burst of water indicate a potential predator>
I have a degree in biology (wanted to be a marine biologist...sometimes life just doesn't work out) 
<I understand... and Mariah Carrey wanted to be a singer>
so I figured that phytoplankton would be my best bet.
<agreed>
Right now I have a bloom of diatom algae so they are probably ok for now.
<helpful>
Naturally, I'd like to rid myself of the algal bloom and then will have to actually feed them. These guys are pretty cool and I'd hate to lose them, especially since that end will probably wipe out my tank.
<indeed a significant mass to be rotting suddenly>
I plan on adding a refugium to my setup anyway, so I'm glad that you think this will help. 
<very much so with the right plants... do avoid Caulerpa for this purpose at least>
But, in the meantime, I may buy some phyto and blenderize it. I'm looking forward to you being at That Fish Place in Lancaster, PA later this month. Perhaps we'll get any opportunity to chat there.
<Looking forward to it!>
Thanks again, Mike
<with kind regards, Anthony>

Bivalve ID- Turkey Wing- Arca species
To Anthony - what is this?
Howdy Anthony! I've attached a picture of something that is growing near the bottom of one of my live rocks.
<very cool... a Turkey Wing bivalve (Arca species)>
Looks sort of like a furry clam, but is long and skinny, and looks as if the shell had formed around a pencil, near the bottom, then the pencil was taken away. (This is where the red spot is, with the shell forming two "hooks".) Hope the pic is clear enough -
<fine enough>
as the critter is near the bottom of the tank, tis hard to get a good angle without taking the rock out of the tank! Is the pic and description good enough for you to tell me what this is? Does
it need a special diet?
<it is a filter feeder. Variable success in captivity. Would likely do best in a fishless refugium. Occasional feedings with meaty juices (small amount) from thawed foods may help.>
(Or, do I need a better picture? - lol) THANK YOU!
>>-Cathy in Texas <><
<best regards, my friend. Anthony>

Oyster Drill snail? 7/18/04
Hello all, I was reading thru your site (one of my favorite things to do in my spare time :)  and I came across some pictures on this page:  http://www.wetwebmedia.com/swsnailfaq3.htm , the comments state that it is an Oyster Drill (Cymatium aquatile) ..... Well, I have searched, your site and all over, and I am not finding any good information on these creatures.  
<they are not used in the aquarium trade for this very reason (hence the void in literature on their husbandry). Tridacnid clams and numerous other desirable bivalves are in greater favor than drab predatory snails <G>>
The few pictures I could find of living Oyster Drills do not look like the pictures on the above linked page, and the only other pics I could find are of empty shells, which tells me nothing at all about the creature.
<there can be considerable variety in form among members of the same family... even in the same genus>
The reason I am asking is because I have one of these things, it was sold to me as "some kind of conch".  I found the hairy shell and spotted body very attractive, so I bought it.  
<this (buying live animals with unknown needs) combined with neglecting to quarantine new specimens is a recipe for disaster in your tank in the long run (introduction of a pest, predator or disease). Please do resist.>
Now, I am wondering, if it is not a conch, and IS an oyster drill, what can I/should I feed it?   Do I need to buy oysters?  Do they have to be live?  Are there other foods it might accept?  What kind of conditions does it need?  It's been in my tank for nearly two weeks, always moving around and active, but I'm worried that maybe it is starving.  Where can I find more/better information on this creature?  Any help is greatly appreciated!  Barb
<the first step is a correct ID of what you have. Without any picture or description of your snail other than general resemblance, it would be unfair and unrealistic for me to speculate. Ask your retailer for more info about where it came from. They should know or their collector/wholesaler at least will know what waters it was collected from. Then take that info and use it to refine your search among the many shell collecting sites. They are your best option in the absence of extensive ID and husbandry info for aquarium use. Anthony>

Bad decisions... wrong species, right admiration 5/27/04
Well, I'm not sure what sea this cowry comes from. I got it from a friend's tank because I'm an invert lover and I think cowries are really cool. ;] 
<fascinating yes. Do check out our coverage of gastropods in "Reef Invertebrates" by Calfo and Fenner too>
I can give you a basic description and see if you can make anything of it.
<nearly impossible from a text description. A photo at least would be helpful>
It's about an inch long, the shell is creamy white w/out any visible markings. The mantle is white w/ dark purple circular spots all over it. The foot is white/translucent w/ the outer perimeter being purple/dark magenta colored. I'm not too sure what it eats, maybe algae maybe snails. Who knows? ;] It is nocturnal for sure.
<It never ceases to amaze and disappoint me that people bring pets into their home without knowing what they eat/need to survive>
Thanks for any info you can give. Morgan Mok
ps: Do you know where a person can get electric scallops? ;] 
<they are near impossible to keep for anything that approaches a natural lifespan in captivity... unless you have figured out a way to magically culture bacteria, nanoplankton and other necessary plankters>
Also, do spiny scallops/oysters (can't remember the name) need temperate waters in order to survive? Thanks!
<ughhh... if you are referring to Thorny Oysters... they are near impossible just the same. These azooxanthellate bivalves are some of the most difficult reef invertebrates to keep alive in aquaria. They slowly starve over a period of weeks to months categorically (very few exceptions). Please be a responsible aquarist and avoid these specimens. Read more about why on our free content website, wetwebmedia.com, or our last book if its handy. Anthony>