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FAQs about Crustacean Behavior

Related FAQs: Crustaceans 1, Crustaceans 2, Crustaceans 3, Crustacean Identification, Crustacean Selection, Crustacean Compatibility, Crustacean Systems, Crustacean Feeding, Crustacean Disease, Crustacean Reproduction, Micro-Crustaceans, Amphipods, Copepods, Mysids, Hermit Crabs, Shrimps, Cleaner Shrimps, Banded Coral Shrimp, Mantis Shrimp, Anemone Eating ShrimpHorseshoe Crabs

Related Articles: CrustaceansMicro-Crustaceans, Amphipods, Copepods, Mysids, Isopods, Shrimps, Coral Banded Shrimp, Cleaner ShrimpP. holthuisi Pix, Mantis "Shrimp", Lobsters, Slipper Lobsters, Hermit Crabs, Squat Lobsters, Crabs, Arthropods, Pycnogonids (Sea Spiders),

Nature abhors a vacuum... consider the milieu. Heteractis crispa (Ehrenberg 1834), the Leathery or Sebae Sea Anemone.

What To Do With The Shrimp Molt? - 06/27/07 Hello WWM Crew, <<Howdy Mathew>> Having done some reading on shrimp molts and whether or not to leave them in (see below) I pose a question. <<Okay>> My shrimp has molted several times but never eaten his shell. <<Doesn't always happen…often the shell simply "dissolves" away>> It sits there for a while then gets sucked up onto the intake. <<Another common event>> In one email Bob states that the shell won't pollute the tank, but is that based on the fact that the shrimp will probably eat it? <<Mmm, no…the shell is made up of bio-mineral elements that usually are simply absorbed back in to the system>> I am having enough problems getting my chemical levels low already. <<No worries re the shed exoskeleton, mate…it will not impart any harmful material to your system>> So should I A: take it out B: Give the guy a chance to eat it but once it's on the intake scrape it off C: Kill the circulation so the shell won't get sucked up and give him a chance to eat it D: Just don't worry LOL <<I wouldn't worry about it…if it catches on your intake screen and restricts flow or you just don't want to look at it then go ahead and remove and dispose>> Thanks for you help, Matthew <<Happy to share. EricR>>

Title: Gourmet Shrimp! WWM Crew Member: Scott F. Question: As for the molting process, It was mentioned once in the FAQ's, But the way I understand it is, I should leave the molted shell in the tank and the shrimp will eventually eat it? Answer: <Wow! If it were me, I'd remove anything from the tank that has the potential to decompose and add to the level of dissolved organics in the water>

Title: Cleaner Shrimp shell leftovers WWM Crew Member: Bob Fenner Question: Is it necessary to remove the molt of my cleaner shrimp from the tank? Sometimes it is a pain to dig out and I was wondering if it will pollute my tank if I just leave it to do its thing? Answer: <Won't pollute... s/b left in... please read through the Shrimp articles, FAQs files archived on http://www.wetwebmedia.com/  Bob Fenner>

Title: Some minor questions and big thank you WWM Crew Member: Bob Fenner Question: He has eaten the shell both times, which I believe is normal Answer: <Yes>

Title: Questions about molting shrimp WWM Crew Member: Bob Fenner Question: I saw the old shells of the peppermint shrimp floating in my tank till I netted them out Answer: You (and others) are encouraged not to remove "old shells"... actually these are often re-incorporated into the (usually) larger specimen that shed them...

Singing, backward moving Crustaceans along the Euphrates?    8/13/06 I'm told hermit crabs sing, but in a Mesopotamian (Ancient Iraq) text the "crabs of the river" are called upon to cry out with a parallel line addressed to frogs. Another text suggests that whatever it is typically moves backward when confronted so I thought perhaps crayfish or river shrimp, but from what I can find Crayfish distribution doesn't go far enough south and I don't remember the species I grew up making any sound.    Can you help me?    Thank You,    Stephen M. Hughey <Mmm, both anomurans (including Hermits) and the other crustaceans mentioned can/do ambulate forward and backward, but I don't know re sound production. Bob Fenner>

Crustacean Molting  12/8/05 Hi,  <Hello Jason> A few weeks ago, a number of my crustaceans molted within the span of two days. At least the fire shrimp and two hermit crabs did this, possibly others that I didn't see. I am wondering what regulates the process, and why they all molted at the same time?  <Growing regulates the process. Water changes can trigger this along with the addition of an iodine/iodide supplement.> Thanks, Jason <You're welcome and Happy Holidays to you. James (Salty Dog)> 

Sand Hopper light experiments I am currently doing an experiment on sand hoppers and are wondering how they are suppose to react to light? <Most are negatively phototropic> Do they like it or would they rather the dark? and does light have anything to do with them knowing the correct direction and their amazing navigation? <Perhaps... you might try experiments with polarized light... maybe on a rig mounted on a turntable... Bob Fenner>  

Crustacean molts... leave them in the aquarium 2/28/05 Hi, I love your site. <thanks kindly> Just a quick question. Should I remove the moltings from all of my crabs and shrimp from the tank or do I let them lay and be degraded or eaten? Thanks! Best Regards, Joe <please always leave them in the aquarium to be eaten or degrade... they are a precious source of Chiton to be recycled. Anthony>

Crab Problem Hi - <Hello there> I have a reef tank, which is doing quite well.  In the process of getting it set up, I bought a "cleaning crew" of assorted critters, including emerald crabs.  It appears that the crabs are catching and eating some of the small fish in the tank - this in spite of my feeding them raw shrimp 2 or 3 times a week.  Is there an easy way of catching the crabs so that I can remove them from the tank?  I do not want to beak down all of the live rock to get them.  Thanks. - Bruce <Some folks have luck making a "feeding sink" of a glass tray, jar on its side, with meaty bait (e.g. a cocktail shrimp sans sauce)... and lifting out when enough of the little buggers are in there. Bob Fenner>

And Now For Our Disappearing Lobster Act....  12/13/2004 I recently introduced a purple lobster into a 75 gallon tank with about 45 lbs of live rock.  I have not seen him since the first day.  I've read they are shy and nocturnal but is it normal I wouldn't have seen anything from him for 4 days?   <This strikes me as a normal thing - I wouldn't be too worried as of yet.> Maybe he's crawled into the rock and died?   <A possibility, indeed, but I think it likelier that the lobster has just found a comfy place to hide out while he gets his bearings in his new place.  Sneak out for a look at the tank well after dark.  Bring a dim flashlight with some red cellophane taped over it (hey, that's one thing Christmas merchandising is GREAT for, red cellophane!!).  Drop in a bit of shrimp or other meaty food, somewhere near the rockwork.  Wait.  With all due luck, once he's settled in some, you'll catch a glimpse of him, maybe get to see him eat.  If so, you'll probably be able to determine where in the rock he spends most of his time.  After a while, you'll probably be able to coax him out any time of day with a bit of food (shrimp, fish, scallop, whatever) in front of his lair.> Should I disrupt the fish by moving all of the rock around to look for him (to make sure he's not dead)? <I would not do this.  I don't believe it's necessary.  Do be testing for ammonia, nitrite, and nitrate, just in case.> Thanks for your help. <Any time.  Wishing you and your lobster pal well,  -Sabrina>

Sending in the clown - flashlight trick? 7/10/04 Could not find an answer to this in the FAQ Archive.  I have an anemone crab (Neopetrolisthes ohshimai) on hold at my LFS  and I am wondering if it will be compatible with my Rose Anemone (Entacmaea quadricolor).   <it is likely to take residence here> My false Perculas have shown no interest in the anemone for 4 months now. Thanks -Ray <I have a wacky suggestion... trust me here: at night when all is dark, set up a small focused light on a timer (like a small book-reading lamp) to shine in a point on the anemone. Do this for up to 2 weeks (consistently! use the time)... and write back to tell us if the clowns went into the anemone. Many theories for why this helps... cant explain it (beyond logical theories of fishes, larvae, plankton being attracted to light). We shall see :) Anthony>

Night Raider? (Mantis Shrimp- Or..?) Crew- <Scott F. your Crew member tonight> Thank you for your continued wisdom.  Two quick questions: 1) Over the course of the last 2 months, we have had 2 small (less than 1 inch) clown gobies mysteriously disappear in our tank.  Likely culprits are a Sally Lightfoot crab and/or Emerald Crab, but wonder about the possibility of a Mantis Shrimp in the tank.  We have heard some clicking at night (very little), but other than that and the disappearing fish, no other signs.  The 45 gallon reef tank also has a coral beauty, cleaner shrimp,  BTA, and several species of live coral.  We have not lost any other fish, or any of our hermit crabs/snails that also inhabit the tank.  Any thoughts? <I'd implicate the Sally Lightfoot, myself. However, there is certainly a possibility of a Mantis Shrimp. You may have to try baiting it out with some meaty foods...> We'll take a flash light out tonight and observe post lights out behavior. <Great idea> Could the Coral Beauty be at risk if we do indeed have a Mantis or Pistol Shrimp? <Yes, there is that possibility, but I wouldn't panic yet. Do perform your nocturnal observation, consider baiting the animal (if it exists), and waiting patiently> 2) We had been having problems hand feeding our BTA, now clown less after our highly aggressive tomato clown had to be removed after beating up our Coral Beauty.  Just this week he began to fully take in the food and digest it.  However, much to our dismay, the cleaner shrimp has decided that the BTA is a good feeding ground for him.  Last night we observed the cleaner shrimp pull the food out of the BTA's closed mouth.   <An annoying habit> He literally stock his paws into the closed mouth and yanked it out  (quite violently) - this occurred about 2 hours post-feeding.  One thought is that the cleaner shrimp is about to molt, and thus over-eating for the upcoming event. <An interesting theory> We are concerned about the BTA's well-being without a protector in a hosting clown.  Any suggestions for how to feed the BTA and keep the shrimp fed/happy at the same time? <If it were me, I'd feed a bit more food than the shrimp could grab at one time. Be prepared, of course, to remove any excess that the anemone doesn't ingest.> I know these sound like basic questions, but didn't see any apropos responses in the FAQs.  Hopefully you can be of some assistance. Christine <Well, Christine- these are very good questions. Unfortunately, like most aquaristic endeavours, there is no one perfect solution to either of them. I would use my suggestions and your excellent insight as a starting point, and use a healthy dose of patience as well! Good luck! Regards, Scott F.>  

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