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Crayfish, Crawdads, Ditch Bugs Behavior

Related Articles: Forget Crawfish Pie, Let's Make a Crawfish Tank! By Gage Harford, Invertebrates for Freshwater Aquariums by Neale Monks, Freshwater Shrimp, Crayfish, "Lobsters", Prawns Freshwater to Brackish Crabs

Related FAQs: Crayfish 1, Crayfish 2, Crayfish ID, Crayfish Compatibility, Crayfish Selection, Crayfish Systems, Crayfish Feeding, Crayfish Disease, Crayfish Reproduction, Freshwater Invertebrates/Use in Aquariums, Freshwater Crustaceans for the Aquarium, FW Crustaceans 2, Fresh to Brackish Water Crabs, Hermit Crabs,

Mostly they hang out, look about for food, check out other tankmates as such.

Crawfish; beh.      2/13/14
My crawfish molted a few days ago but the shell did not come off right. By the time I woke up he seemed to be stuck in his old legs. Is abdomen and tail were off but he was laying on his back with his legs up. They seemed to be half out of the shell because it seemed like the "shell "was a tangled mess. I later realized that those were his actual legs. During the molt not only did his two front claws tear out but all of his legs are crumpled and broken. Now he just writhes on his back. It's very upsetting and I don't know what to do. I keep expecting to find him dead but he's still hanging in there somehow. I tried feeding him by gently lowering food to his mouth on a skewer but he was more frightened than hungry. Is there anything I can do to save him?
Thanks
Shannon
<Hi Shannon. We get a message like this every week or two. Invariably, the crayfish was being kept without supplementary iodine (sold for marine aquaria, and used at half the dose on the packaging). Do have a read here:
http://www.wetwebmedia.com/CrayDis4.htm
Nothing you can do to help now, but the next moult may fix things if the crayfish survives, in which case immediately using iodine supplement will be the key to success. Good luck, Neale.>

blue lobster; beh.       1/19/14
just wandering why my pet lobster just leaps up almost jumping out of my tank. What does that mean.
<... Something not to their liking... water quality likely; or tankmate/s.
Bob Fenner>

Crayfish behavior question...      3/9/13
What are the crayfish doing when they just sit stationary and slowly sway their appendages back and forth. The motion is reminiscent of a rocking chair... back and forth, back and forth.
<If you mean the appendages around the head, these are mostly sensory, either sampling the water directly, or else directing water towards sense organs.>
Also, I swear it's possible that they can regrow appendages without moulting. Am I correct?
<Unlikely; crustacean appendages grow back with each moult because that's when their skeleton (which is external) gets "upgraded" to the newer, bigger size. Cheers, Neale.>

blue crayfish acting strange     3/7/13
Hello-
<Hi Ann>
I have a blue crayfish in my classroom aquarium that has been acting strange for a couple of weeks.  I have had the crayfish for about 6 months.
 It is in a 30 gallon aquarium with some rosy barbs and neon tetras.
<Surprising that these species all get along here; temperamentally and water-quality wise>
 She ( I think it is a she) has a log to hide in, but has not been staying in the log for the past couple of weeks, instead choosing to walk around and sometimes lay on her side.
<Laying on side... could be reproductive behavior, evidence of nutritional deficiency... or nothing>
Also  for  the past couple of weeks she has been curling her tail under her body when she walks around.  When she uncurls her tail she is picking at her stomach with her little back feet.
<How long have you had this animal?>
 Sometime she puts the tip of her tail down on the floor of the aquarium and raises the back half of her body and feet off of the floor.  My students are convinced that she is pregnant and that she is going to have babies any day now.
<Mmm, can you see eggs?>
 I am not so sure because she is the only crayfish in the tank, and I do not believe that they are asexual. 
<Are dioecious, from the Gk. meaning "two houses", boys and girls...>
I have tested the water and it is ok, but I did a partial water change anyway.  I would definitely be interested in any insight that you may be able to offer.
Sincerely,
Mrs. D
<Mmm, well, IF the one was in the presence of a male before your acquiring it, there might be a packet of sperm that was transferred... But females will/do "go through the motions" often w/o actually producing eggs, and of course, viable young. I would have you review what we have archived:
http://www.wetwebmedia.com/FWSubWebIndex/crayfishbehfaq.htm
and the linked files above. Are you providing Iodide/ate? Is there sufficient alkalinity here? Has this specimen molted in recent times? Bob Fenner>

crayfish molting during pregnancy?    1/30/13
Hi WWM Crew,
<DC>
I have a pair of bright orange crayfishes (I'm not sure as to what species they belong to, please see pictures) and they were already mating  just a few seconds after I placed the male on the female's tank. After that, they were mating non-stop (like every 15 minutes?) so I searched the web to check if this was normal and found out that you had to separate them after mating because the male is just going to replace the old sperm plug and just repeat the cycle. Now after 1 week, the female molted! So my questions are:
1. is the sperm deposit affected by the female's molting process? do I need to re-introduce the male?
<Is... shed w/ skeleton, unless already used. I'd hold off on introducing the male. It may well eat the other>
2. when a male crayfish is in "form 2", he has to molt to be in "form 1".
Then if he molts again after that, will he go back to "form 2"?
<Usually will change back from "juvenile" in time, molts, w/ good conditions... see WWM re systems, nutrition of Crays>
Thanks,
Daddy Chong
<Welcome. Bob Fenner>

M, F

Re: crayfish molting during pregnancy?   1/31/13
Oh I see.. Just 1 quick follow-up question.. What species do my crayfishes belong?
<Don't know... would search Google images re. B>
Thanks,
Daddy Chong

Crayfish, systems  - 1/25/13
Hi WWM,
<Ashley,>
I have a problem that you may be able to help with. I keep a Red Claw Crayfish (Cherax Quadricarinatus) and he has chewed through the cables to the filter and heater in his tank causing a very low electrical current to pass through the water.
<Do give him something else to eat; these animals are herbivorous in part,
and need something to chew. Have you tried plain vanilla Pondweed as sold for Goldfish?>
I have tried positioning the heater and filter so the cables are out of the water but he climbs up them and pulls the cables back into the water.
<Is what they do. Crayfish aren't really amphibious as such, but they do explore, and they do clamber through swamps from one pool to another.>
The electric current doesn't seem to affect him as he is moving and feeding as normal. Is there anyway of making the cables 'chew proof'?
<For sure. Wrap with pond-quality plastic liner or mesh. An external heater (e.g., Hydor ETH) may be more effective, particularly if connected to an external canister filter (some of which, like certain Eheim models, have built-in heaters anyway).>
Thanks in advance,
Ashley
<Cheers, Neale.> 

white and blue crayfish, beh., fdg.       8/19/12
I have a white crayfish and a blue crayfish in a 90 gallon tank I also have a common brown crayfish. The tank has lots of caves and plants but the white crayfish and blue crayfish are sharing a cave. They have built a wall in the entrance of the cave and haven’t come out for 2 weeks.
<Odd. But do bear in mind Crayfish are largely nocturnal, and prefer to feed at night.>
I have seen them mate several times and they never fight. I recently knocked some of the wall down to see if they are alive and they are. I thought that crayfish would fight is it normal for a blue and white crayfish to live in the same cave together?
<Not at all normal! You are lucky. Of course, the acid test is what happens when they moult; that's often when fatalities occur.>
I am also worried that they are not eating. Should I just leave them alone?
<Yes. Naturally, check the aquarium is working properly in terms of water quality (is the filter okay) and water chemistry (shouldn't be soft or acidic). Review diet, and remember they need green foods, a source of calcium (unshelled shrimp are good) and some use of iodine (you can buy iodine-enriched foods for crayfish, but adding iodine drops as sold for marine aquaria at 50% the quoted dose seems to work best). There's a good review here:
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
Cheers, Neale.>

Blue Yabby... beh. 1/9/12
Hi there,
<Danielle>
I have had a blue Yabby in a filtered 200L tank for about a year now.
As s/he moulted approx 3 times last year, I am guessing its age to be 1-2yrs old. He is approximately 16cm from tail to end of his pincer.
Last night, I came home to find one of his pincers lying beside him. I was startled and quite upset, until I read up on your site that this can happen and it's not fatal.
Q: Will it grow back?
<If there's sufficient nutrition, suitable water quality... likely so>
Q: S/he also seems to like munching on it, should I remove it or leave it in the tank?
<Leave it in... provides replacement biomineral and nutrition>
I have also tested the nitrites, ammonia and pH levels. The nitrites and ammonia levels are fine (I do a 25% water change & scrub the rocks-with water- every 10 days & neutralise the new water). However, from external research, my concern is the pH level. It's at 6.4, which according to my research is too low.
<It is too low. Do read further re necessary biomineral and alkalinity...
here: http://www.wetwebmedia.com/FWSubWebIndex/crayfishsysfaqs.htm>
Q: Can you please advise the best way to increase the pH level without harming him?
<Read here re: http://www.wetwebmedia.com/FWSubWebIndex/fwhardnessfaqs.htm
I also only feed him pellets but tomorrow I will go and buy some algae food, i.e. that contains Spirulina. As per your advice, I'll also buy some iodide to put in the water and only add half dosage.
<Good>
Below, I have attached some photos of him, of his detached pincer and the attached one. Both pincers appear to have brown spots on them. The detached one looks like it has a lesion on it. S/he's still pretty active and alert but I just want to make sure I get this in time.
Q: Is it likely s/he'll lose his other pincer due to the brown spots?
<Mmm, can't say. Depends on the cause/s of the ecdysis>
Q: Could it be possible s/he have removed the infected pincer?
<Mmm, yes>
Q: S/he is forever cleaning itself. Is this normal?
<Yes>
I look forward to your advice.
Thanks
Danielle
<Welcome. Bob Fenner>

Re: Blue Yabby 1/9/12
Hi Bob
Thanks for the advice, I'll action today.
Cheers and happy new year.
Danielle
<And you dear. BobF>

why is my Procambarus alleni pale after molting. Reading 9/6/11
Hello, Your forums are useful and informative.
<Appears you haven't read on WWM though>
I recently bought a blue crayfish. I did a lot of research, and I'm sure its the Procambarus alleni crayfish. He is about 4 inches long and was very blue when I bought him. After a week in my tank, he molted and I removed his old shell the next day (I know better now). Anyway he is very pale (almost white) and he does not look blue at all. he is eating normally and seems comfortable i.e. moving around his tank and so on. He lives with two (baby) iridescent sharks. It has been nearly a week after he has molted and he looks the same. Please help! Thanks Avinash.
<... what re chemistry of the water here? Levels of Ca, Mg, Alkalinity? Use of iodide/ate? Foods/feeding. Please read here: http://wetwebmedia.com/FWSubWebIndex/crayfishbehfaq.htm
and the linked files above. Bob Fenner

Cray fish molted .. what to do with old shell ? 6/22/11
Hi,
<Hello>
My Cray fish just molted this morning and she looks fine .. all in one piece. We are wondering if we need to keep the old shell in the tank or can we remove it?
<Leave in... may well be consumed... Read here:
http://wetwebmedia.com/FWSubWebIndex/crayfishbehfaq.htm
Thanks
Simmi Manoj
<Welcome. Bob Fenner>

Rock's Exoskeleton 2/6/11
Hi Crew!
<Kat,>
Rock (my crawdad) just went through a molt and it's all in one piece - how long do I leave it in the tank if he doesn't eat it?
<As long as it takes, certainly 3-4 nights. Recycling the calcium in the shell is crucial. Do also remember to dose the tank with iodine as sold for use in reef tanks, albeit at 50% the quoted dose for the reef tank; without iodine, crayfish don't seem to be able to repeatedly moult successfully.>
It's kind of creeping me out... LOL!
<Then don't keep crayfish!>
Thanks,
Kat
<Cheers, Neale.>
re: Rock's Exoskeleton

Thanks Neale,
I'll pop out and get some iodine for him... :)
Kat
<Real good. Cheers, Neale.>

Crayfish changing colors? 1/12/11
Hello I have had my crayfish for about two months. It has molted twice in that short time span. My question is about color. When I got pinchy he/she was a bluish purple color. Now it is very dark blue with stripes and at the joints a whitish color. I've looked up crayfish with this coloring and the closest I've come is Cherax peknyi. I have looked at numerous pictures but haven't seen any with the original light blue coloring. I just want to make sure it is fine. He/she lives in a 55gal with 4 tiger barbs 7 black skirt tetra 2 Chinese algae eaters
<Do keep your eyes on these... see WWM re>
and 3 Plecos.
<Which species?>
Dark blue sand as substrate. Two 60 gal filters and ammonia 0 nitrite 0 and nitrate 5ish. Thank you very
much
C. Conner
<Umm, Crayfish do change colour (and markings) with environmental, nutritional influence... some do change as well with age, development... You might want to take a few photos, send them off to the specialty FW crustacean sites w/ your query. Bob Fenner>

Question for your staff... 12/25/10
I am having a discussion with a friend of mine who's grandfather told her that a crawfish tail grows back when they are torn off. I am of the impression that since she was a little girl when she was told this, that
she was told this so that she wouldn't think that she was killing them and being inhumane. So to settle the question we have searched Google and ask.com to see if this is myth or real. Your site is the closest to having similar questions answered and I was hoping that you could help us answer this question. If you could reply within the next couple of weeks that would be great. I know that it is the holiday season and that you probably won't get back to me as quickly as during a regular working week. Thank you for your time and knowledge in this particular field.
David
<Hello David. No, crayfish (crawfish) cannot regrow their tails. Removing their tails is indeed traumatic, and because the tail is highly muscular and contains the organs used for breathing, the gills, removing the tail will kill the crayfish quickly through blood loss, shock, and suffocation. Your friend is perhaps remembering incorrectly something her grandfather told her. Crayfish can, in theory at least, regrow their limbs. They can do something called autotomy if a predator grabs hold of a claw or leg, autotomy being self-amputation of a limb. The leg or claw snaps off, the crayfish uses its tail to quickly swim away, and the predator hopefully fails to re-catch the crayfish. The amputation is controlled by the nerves, so its a voluntary thing, but it is still quite stressful for the crayfish and used only as a last-ditch attempt to escape a deadly situation. At the next moult a small bud-like limb will appear where the leg or claw was lost. With each moult (each one a month or so young, less often as they age) the bud gets a little bigger and more similar to the leg or claw.
After six or more moults the claw or leg will be approximately "normal" though re-grown claws are usually smaller than the original claw. Because older crayfish don't moult often, if at all, older crayfish have a very
limited ability to re-grow missing limbs and may not ever properly do so.
Crayfish don't grow missing tails because their "tails" aren't limbs but actually their abdomens, and we call them tails purely because it's convenient to do so, not because they're anatomically similar to tails of,
say, lizards, which can indeed shed the tips of their tails if needs be.
Hope this helps. Cheers, Neale.>

crawfish lost claws in moulting, reading 10/16/10
Our crayfish moulted recently but this time he lost both of his front claws.
<Mmm, happens... Usually due to nutritional deficiency and/or water quality issue/s (lack of alkalinity, biomineral content, iodide-ate>
When my husband found him, he was lying on his back at the bottom of the tank. We were afraid he was dead but when he tried to fish him out of the tank he shot all around but didn't seem to have very good control as to where he went or how he landed. I don't recall him having lost is claws in previous moults and we've never seen him lying on the bottom of the tank like that before. He seems to be doing a little better now, hiding in the castle, but at least he is upright. Is it normal for them to lose both claws when they moult?
<Mmm, no>
Also, I noticed several postings where iodine supplements are recommended. Should we be adding iodine to the water?
<Yes... actually iodide-ate>
Will the iodine have any adverse effects on any of the fish in the tank with him?
<Not if "properly" dosed>
Thanks for your help.
Lynn
<All you need to know is archived on WWM. Start reading here:
http://wetwebmedia.com/FWSubWebIndex/crayfishbehfaq.htm
or learn to/use the search tool linked on the site on every page. Bob Fenner>

crayfish concern... beh., hlth. -- 10/11/10
I have a concerning question about my crayfish. He is 3 years old and pretty big now, he's blue and really shy. He use to always stay in his cave but recently I always see him walking around my tank, he even tried to get out today by climbing up the bubble cord. I noticed that he has these long fuzzy transparent things about his legs and I was wondering what they are and if this is bad. I've never seen it on him before and I'm scared that he's going to die. I had him at my mothers in a different tank and she never fed him and the water was pretty gross because she hated him and refused to take care of it. When I got him back I put him in my clean tank and I feed him everyday. Will the transparent fuzzy things come off?
<Hello Stefanie. Chances are that the fuzzy things are relatively benign parasites you needn't worry about too much. They're unlikely to be related to your crayfish's odd behaviour. In fact things should improve each time he moults if you remove the moult so he cannot become reinfected. Because crayfish recycle calcium this way, be sure to provide an alternative source such as unshelled shrimp or whole, frozen lancefish (you can buy these from pet stores). As for the odd behaviour, one of several things could be
amiss. Check water quality first, and water chemistry second. Water quality should be good, ammonia and nitrite levels at zero. The tank should be reasonably big -- 15 gallons would be about the smallest for a large crayfish -- and filtered. You should be doing regular water changes, 25% every couple of weeks. The water should be hard and basic. If you live in a soft water area try adding to every 5 gallons half a tablespoon of Epsom salt, half a teaspoon of sodium bicarbonate (baking soda), and half a teaspoon of aquarium salt, ideally marine salt mix but ordinary aquarium salt will do. Supplemental iodine is important for moulting; use the stuff sold for marine aquaria, but at a half dose. Without iodine, deformities are common, as are fatalities. Basically check everything is as it should be.
http://www.wetwebmedia.com/ca/volume_1/cav1i4/crayfish/crayfish.htm
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
http://www.wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm
Cheers, Neale.>

stressed crayfish
Will stress induce molting in a crayfish? 9/13/10

<Can't think why.>
One of our crayfish was attacked by another one ( a mishap while the kids were observing them in the sink!) and lost a claw - traumatic, I'm sure!
<Indeed, and without a claw crayfish are less able to defend themselves, making cannibalism much more likely. Crayfish are territorial and fairly aggressive animals. Re-growing missing limbs also wastes energy, and that
can set crayfish back relative to their peers, with bigger ones bullying and/or eating smaller ones.>
He then molted that very night. This posed a great question for my science-minded kid - was it the stress or just coincidence?
<Likely the latter.><<Mmm, am not so sure... Perhaps the molt after the autotomy (tossing of the "free" limb to avoid outright death... has survival value. RMF>>
Thanks!
Leslie
<Cheers, Neale.>
More re: stressed crayfish
9/13/10
He then molted that very night. This posed a great question for my science-minded kid - was it the stress or just coincidence?
<Likely the latter.>
<<Mmm, am not so sure... Perhaps the molt after the autotomy (tossing of the "free" limb to avoid outright death'¦ has survival value. RMF>>
<Would disagree Bob. It takes several days for the hormonal changes prior to moulting -- reabsorbing calcium from the old shell, absorbing extra water to expand the new shell, and so on. Moulting itself is the point at which a crustacean is at its most vulnerable, whereas a lost limb is a fairly trivial issue. I can't see how a crayfish could speed up moulting, or why it should want to. But all speculation! Cheers, Neale.>
<<Mmm, I still don't know re. Please see the first few citations here: http://mail.wetwebmedia.com/Default.aspx#page=/Main/frmMessages.aspx?user=crew&folder=sent+items&mapped=false&leftnav=true|section=UserEmail
B>>

FW Lobster antenna missing -- 08/06/10
Hi Crew,
<Hello Cap,>
I just purchased a Tiger Lobster
<Crayfish'¦>
and did not see that one of the antenna are missing. It looks to have had the whole socket pulled off. In the photos there seems to be a curling growth returning.
Will this ever possibly self correct or did I purchase a 'sensory challenged crustacean'?
<Will grow back *assuming* good water quality and the use of an iodine supplement at 50% the dose recommended for marine aquaria. This latter actually ensures good moulting generally, and iodine deficiency is apparently a common reason why crayfish fail to moult properly in home aquaria.>
Thank you for your kind attention.
Cap
<Happy to help. But please, next time keep your images down to 500 KB; we do ask for this where you got the e-mail address, and if people ignore this and send 7 MB images like you did, that gums up our e-mail allowance and causes other people to have their messages bounced back unanswered. That's not fair, is it? So please, help us to help you. Cheers, Neale.>

Crayfish Question... beh., not good -- 05/21/10
Hi, I am trying to find out what it means when a crayfish turns up side down, the crayfish is still a live in a 10 gallon tank she has every thing it needs to be healthy I just cant figure out why it keeps turning on its back like if its going to die, but my daughter just turns it back over and it goes for a good hour before it turns on its back again what could be the problem. Please help this is for my daughter I would hate to see it die on her. thx Jesse
<Hello Jesse. No, it's not normal. In fact it's often a bad sign. Crayfish sometimes fall over if the aquarium just has a plain glass bottom, because their legs can't grip glass at all. Fine gravel or sand is best. Make sure there isn't an copper or anything poisonous, e.g., insecticide, getting into the water. Make sure the water is adequately filtered and if necessary heated. Hard, basic water is usually essential for most crayfish species.
Supplemental iodine is important for moulting; use the stuff sold for marine aquaria, but at a half dose. Without iodine, deformities are common, as are fatalities. Basically check everything is as it should be.
http://www.wetwebmedia.com/ca/volume_1/cav1i4/crayfish/crayfish.htm
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
http://www.wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm
Cheers, Neale.>

Crayfish beh., moulting 3/6/10
Hey guys,
I have a question about my crawdad. I took him out of my spring about a year ago. He's been doing great in my fish tank. I put a deer skull in there for him and he's made a pretty cool place for himself underneath.
Well, I had noticed I haven't seen him for a while and found him wedged under the skull and he hasn't moved for a little over a day. He usually comes out everyday. I'm afraid of touching him because I'm not familiar with their characteristics during molting. I've been searching but can't really find anything. I don't want to hurt him if he's alive and I also don't want him in my fish tank if he's dead. Long story short, do crawdads basically act dead during molting.
Thanks,
Evan
<"Play dead" is perhaps too strong; they do become retiring for a few days, as their skeleton is shed and for a day or two afterwards they wait for their skeleton to harden up. That said, because crayfish often have problems when moulting, it's well to understand their requirements. Among other things, lack of iodine tends to cause problems. The addition of marine aquarium iodine drops, at 50% the dose recommended for use in reef tanks, will do the trick nicely and is highly recommended. Crayfish having problems moulting become moribund, lethargic, deformed, and quite possibly end up dead. Cheers, Neale.>

Yabby Question, beh. -- 02/22/10
Hi there!
<Hello,>
I'm really stumped on this one. I'm a bit worried about my yabby (just a regular Australian dam yabby). I've had her almost two years, in which she has doubled in size, and she recently moulted for the second time while in my care.
<Well done.>
I got her a bigger tank, with more hiding places and things to play with. I treated the water as per normal, and she wasn't doing anything out of the ordinary for a few days. Just exploring and climbing and eating and hiding.
However for almost the last 24 hours, she's been just standing around various parts of the tank, rather still, almost trying to make herself look bigger or something. Sometimes she props herself up higher using one of her claws for balance, but her body is almost entirely off the ground, and her tail is tucked under. I've seen her eating in this bizarre posture, but I'm just concerned that she isn't happy with something, either regarding her new tank or her recent moult. It's rather strange behaviour for her. Also I think she may be a he. But I'm not sure!
<It is possible that the Crayfish is posturing to its reflection, either trying to scare away a rival or attract a mate. Sexing Crayfish is notoriously difficult, and probably impossible to do reliably with juveniles (does depend on the species thought). Sexually mature animals have differently shaped genital openings. This will vary from species to
species, so you'll need to identify the species you have, using a Latin name ideally, and take it from there. In some cases, males and females have different colours or differently shaped claws, but this isn't common.>
Thanks a lot for any help you can give me!
<I wouldn't worry unduly, especially if the Crayfish is otherwise healthy and happy. Cheers, Neale.>

Blue after molting? 1/11/10
Hello, Sorry to bother yet again...but I need help (again). (And your site is AWESOME by the way!)
Happy to report that Crash, the previously red crawfish, is still alive, he just went through his second molt, and he's BLUE! is this normal? Will he stay blue? It's been at least 24 hours since the molt. Just worried that we might miss something, we've gotten quite attached to the little guy.
I have attached a photo (I hope that's okay) his old shell is in the log on the right, so you can get an idea of the color he used to be. Thank you,
Brenda
<Yes, is quite normal. Shell colour depends on diet, water chemistry, age, and various other factors. But do make sure water chemistry is hard and basic, and adding iodine to the water (via the marine supplements widely sold, at half dose) can ensure successful moults again and again. Cheers, Neale.>

Re: Blue after molting? 1/11/10
So is blue good or bad?
<Neither, but you should be aware that seriously imperfect moults can kill crayfish, so if anything seems slightly amiss, take it for a potential warning, and review overall conditions. In soft water for example, the new shell is unusually thin, and this can result in a much paler colour than otherwise.>
He mostly gets algae discs, shrimp pellets (Which he doesn't eat), and the occasional thawed and peeled frozen shrimp (does this give them some iodine supplement or is it the wrong kind of iodine?)
<Iodine comes as a liquid supplement you add to the water. It's not expensive, and at a half dose relative to a marine aquarium, very economical to use. Some companies make specific foods formulated for crabs, crayfish and other crustaceans (e.g., Sera, JBL) and these make good staples. Whether or not they completely remove the need for iodine supplement is unknown to me.>
Thank you SO much, your so very helpful!
<Glad to help.>
Brenda
<Cheers, Neale.>

Yabby is acting weird 9/30/09
I purchased a blue yabby (Luca) about a month ago and he is doing well.
However, the paradise fish (Sydney) I bought is MIA. I am assuming that Luca has eaten Sydney,
<Well, yes. Crayfish are herbivores in the wild, which is why you feed them mostly greens with just the odd bit of white fish fillet or unshelled prawn. But they can, and will, eat almost anything they can catch.>
but he almost seems lonely now.
<He's not. These are territorial and aggressive animals.>
He used to be very active and greet me when I walked up to the tank (now he just stays in his "cave"). Also, he has begun "trimming"/eating the plastic plant that I have in the tank.
<He's telling you this: feed me some plant material! These are largely vegetarian animals, and would eat a lot of decaying plant material. In captivity they often chew on plastic and sponges if they can't get anything
else.>
Lastly, I have Malaysian driftwood and he seems to be eating that as well.
<Indeed!>
I feed him every day (alternate between shrimp pellets and algae wafers).
Why do you suppose he is acting strangely?
<He's hungry. Stick some Sushi Nori in, or perhaps some cheap aquarium plants, such as Elodea. Lettuce and cucumber usually go down well, too. Let him graze away.>
One last thing... I noticed his antenna things are getting shorter and the tips look a bit discolored what can cause this?
<Does happen. Possibly physical damage, possibly a water quality or water chemistry issue. Review conditions in the tank, and review diet, in particular how calcium-rich his diet is. Do read these articles:
http://www.wetwebmedia.com/ca/volume_1/cav1i4/crayfish/crayfish.htm
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
Should give you some ideas on diet.>
Thanks,
Karen
<Cheers, Neale.>

Lobster hasn't molted for months... Child, English, reading 9/1/2009
Hello,
My name is Michael, I've got a lobster (about 3.5-4 inches probably, its a pail red, almost pink), I've owned the little critter for a good 3 or 4 months, at least now and it's only molted once.. I find this to be odd because I had owned a blue lobster a while back with an ex and it molted several times before reaching the size mine is now. Hasn't molted but seems to keep growing,
<Mmm... Michael, maybe it is molting and you're just not noticing. Crustaceans can't grow w/o such>
also seems perfectly healthy mind you and Im not complaining because his tank mates are 3 red belly piranhas(roughly the same length maybe a bit shorter).
<Yikes! Might well consume the "bug" when it is soft-bodied>>
They seem to be a good tank mates thus far as well- only ever tried to attack the lobster once and he put the fear of the claw in'em by pinching one between the mouth and eyes, i like to give my piranhas pellet food, and frozen and veg. when i got stuff they'll eat and of course live feeders (people say they are super unhealthy, ect, ect,
<No such word... etc. is the contraction for the Latin "et cetera res" (= and other things)>
i don't really care about that cuz i
<...>
balance the diet and they are what looks to be good exercise in my opinion), - my lobster and 2 trap door snails clean up after them. The snails i didn't really expect to last long so im not overly concerned as they were bought as a 'treat' but became cleaners.. Im really just curious why my lobster seems healthy, and growing.. yet not molting? any ideas? i don't know pH or nitrates, i keep good filtration, and keep up on top of the overall tank maintenance. Oh and the last time he molted, which was also the first time (in his life in my aquarium at least), was months ago shortly after i first got it.
But mind you I've just noticed my piranha seem to be breathing slightly more rapid then before, could that just be from a lack of bubbler combined with body growth (larger body needs more oxygen, right?)?
<Yes... dangerous>
Thanks for you're time, hope to hear from you soon - i got nothing dying though so take care of those with sick fish first..
<Most often this situation is a matter of nutrition and/or low alkalinity and/or biomineral content. Read here:
http://wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm
and the linked files above. Bob Fenner>

Sluggish crawfish 4/14/2009
My son inherited a crawfish from school, He calls it an Australian Crawfish (my husband is from Louisiana and thinks he has it all figured out) We have had him for almost three weeks, and he has been doing great so far. We have him in a 5 gallon tank almost full of water with a filter (not sure if we have too much water in there) he has a log to hide in and a couple of fake plants that he likes to chew on. We have had him/her on a diet of mostly algae discs, and so far he has been enjoying them. Tonight we noticed that he hadn't touched his algae disc from this morning, and didn't seem to interested in the one he got tonight. Water temp is the same as last week, and ph levels all seem to be on target. Is it possible he is getting ready to molt?
<Mmm, maybe... lethargy is common in these cases>
Or do we have a sick crawfish on our hands?
<Perhaps>
Any help would be greatly appreciated.
Sincerely,
Brenda Collins
<Oh! One of my sis' names... Could be that you have a "cycling issue" going on here... and/or a lack of alkaline reserve. These possible chemistry issues and more are detailed in our archives. Please read here: http://wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm
and the linked files at top. Bob Fenner>

Odd crayfish behavior -- 02/12/09 I was recently (about 4 weeks ago) given a crayfish, Ruckus, from a pet store manager and I am really enjoying keeping and caring for it. It can be quite humorous to watch. I do have a problem though. Tonight my crayfish started exhibiting a strange new behavior; I have Googled and Googled and can't find much of anything dealing with it and I am hoping that you could shed some light on this matter for me. Ruckus has started to sit with it's tail curled under and while it is doing this, it pushes up with one claw while all of the other legs move in a walking like manner. Sometimes it almost looks like Ruckus is obsessively cleaning his legs and claws; sometimes he/she just rhythmically waves one side of the body's legs. It almost looks like obsessive compulsive behavior. Ruckus has molted four times now but every time it has happened I was asleep so I am not sure if this is an indicator of a molt about to happen or if it is the beginning of a problem. I currently have Ruckus housed in a ten gallon tank with a power filter and an air pump supplying air (I tried plants but Ruckus earned his name by eating them all and creating a huge ruckus in the process). I have three hatchet fish in the tank with him/her for company and because they are top dwellers I don't need to worry to much about them meeting untimely ends, or at least I hope so, and I had snails but Ruckus really liked them and I don't want to keep them stocked anymore except for the occasional treat. I do 50% water change every week on all my tanks and have never found any ammonia in any of my tanks. Any ideas or insight that could help me understand this behavior would be greatly appreciated. Thanks Shawn <Hello Shawn, while I doubt crayfish can get OCD, it's not uncommon for animals to develop quirks of various kinds, just like people. Genetic abnormalities, damage to the nerves, malnutrition (particularly vitamin/mineral deficiencies) can all cause problems. So review basic care, in particular double checking your crayfish is getting lots of green foods (they're mostly herbivores in the wild) and that you're adding Iodine to the water periodically (use a marine aquarium Iodine supplement, but at a half dose). As for the Hatchetfish, they shouldn't be at any great risk assuming the tank is reasonably deep, but generally I don't recommend mixing fish and crayfish. Do review this article on Crayfish in Conscientious Aquarist, here: http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm Cheers, Neale.>

Difficulty molting 11/09/08 Hello, I have a crayfish, Marilyn, for 1 year now. She was brown as a baby Cray, but has since turned blue. She has molted regularly throughout her life. This morning I had the privilege of witnessing her molt. She has shaken her way out of most of the exoskeleton, except for the part on her back, that goes down her sides and over her head and face. It has been 7 hours now. Fuzzy white stuff is coming out and she looks uncomfortable. I have attached a picture of where you could see the separation. It looks like it should just pop off. Is there anything I should do to help her, or should I just leave her alone? Sincere thanks, Lisa <Hi Lisa. Crayfish experience molting problems for a number of reasons. The two most common are iodine deficiency and poor diet. The iodine issue is very common easily fixed, at least preemptively: buy some marine aquarium iodine drops, and add to the tank at 50% the dose for a marine aquarium. As for diet, you must always remember crayfish are herbivores. Some people make the mistake of feeding them just meaty foods! At least 75% of their diet should be green things: algae wafers, tinned peas, blanched lettuce, etc. As for the rest, try to make this sort of thing calcium rich: unshelled prawns, whole lancefish (bones!) and so on. There's really not much you can do right now. Adding iodine to the water could help, but that's about all. If you're lucky, she'll pull through and without too many deformities, and subsequent molts will put them right. Don't try and "help" her out -- you're more likely to damage her in the process. Cheers, Neale. PS: Next time send small images, around 500 kb; three different 2-point-something megabyte images pretty well fills up our 10 MB e-mail space, meaning some other folks might get their stuff bounced back!>

Red claw crayfish, sel., beh. 6/4/08 Hi! I was just wondering about keeping red claw crayfish, Cherax quadricarinatus, and have been reading on WWM about keeping them. I was just wondering though, how interesting are they compared to other crayfish? I have a Louisiana red P. clarkii and I find her active and always walking about. <Yes... I've kept this species off and on for years... very interesting IMO/E> Are red claws a lethargic type of crayfish spending most of their time hidden? <Much more than Procambarus> Plus some places I have read says they are not very aggressive towards their own kind, while other places say they are always on the lookout to murder each other. <The genus is more like the latter in my experience> Have any of you had any first hand experience with keeping these critters? <If hungry, crowded...> Thanks! Don Smith <Welcome. Bob Fenner>

Crayfish lost both claws 5/16/08 Hello I started out by Googling my question and that brought me to your site. I looked around there, but still haven't quite found the answer. In any case, my daughter brought home a crayfish from school yesterday. The only information I received with the crayfish was it needed a tank with a filter. <All else being equal, this is correct. But do add some sort of "cave" to the set-up; a ceramic flowerpot will be ideal. Crayfish are retiring, nocturnal animals and need hiding places.> I bought a new aquarium set up with a filter and got it all ready for the crayfish (with fake plants, a cave made out of flat rocks, gravel, etc.) The crayfish seemed okay, as far as we could tell (active, checking things out). We tried feeding it lettuce, carrot shreds, and fish flakes, but it didn't seem interested. <Do try a mix of plant and animal foods. A raw peeled shrimp or small piece of white fish would be an ideal food to tempt the crayfish into feeding.> This evening my daughter looked in the tank and noticed that both of its claws had fallen off! <Does happen when stressed or alarmed.> We were both shocked as it doesn't seem to otherwise be molting. Have we done something terribly wrong? I used water from our well, which we used without any difficulty with other water-pets in the past. It does have a significant sulphur content, but I didn't see anywhere in a Google search that this would be a problem. <Should be fine.> What should we do? I feel terrible if the poor thing is being poisoned somehow! Also, could the tank be too small? The pet store said 5 gallons was okay, but now I keep reading that 10 gallons is the right size. <The size of the tank is not in itself the issue, though I would agree that a 10-gallon tank is much preferable for all sorts of reasons, the prime one being water quality management. In brief, small tanks tend to have poor water quality, and that will stress any pet, including crayfish. Filtration and water changes mitigate this somewhat, but not completely. This is why we routinely tell people starting in the hobby to use 20-gallon tanks. Maintaining a 20-gallon tank is ten, twenty times easier than a 10-gallon tank, and probably a hundred times easier than a 5-gallon tank! In any case, use a nitrite test kit to make sure the water is clean, and if not, do water changes and improve filtration as required.> It seems to be "healthy" aside from the claws, but I don't know how to judge, really. <With crayfish, the antennae and the mouthparts should be constantly in action; the eyes should be alert and the animal responsive to movement outside the tank. Whilst they can feed without their claws, and will regrow them slightly at each molt, this may take many months and the claws will always be a bit undersized relative to the rest of the animal.> Thanks in advance for your help! <Cheers, Neale.> Yabby shedding problem, using WWM -- 04/21/08 Please help us! We have a pet Yabby called Pinchie who has recently shed and seems to be having some serious problems. We have had him for almost 4 years and have never encountered a problem. It is like he has shed his claws and broken the joint in his new ones. they bend under him at an odd angle. Should we remove them? <Mmm, no... they'll be shed in turn when conditions and nutrition allow...> He is upside down at all times and his head is a turning a brownish/red colour. He is usually a whitish blue. He is still moving but intermittently. As far as his tank goes nothing has been done any different. We are at a loss at how to help him. Looking forward to hopefully ending his obvious discomfort. Thank you for your time. Rach & Jess. <Something very amiss here. Try using the search tool (as requested before writing us) here: http://wetwebmedia.com/WWMAdminSubWebIndex/question_page.htm with the terms "crayfish shedding problems" and read the cached views... Something awry here with water quality and/or feeding... as detailed on WWM. Bob Fenner>

Blue lobster beh., hlth. 01/08/2008 Our behavior of our lobster is weird, he is in a tank (55 gallon) with a red devil. The red devil is not bothering him and we have had him approx. one month. We have been feeding him wafers, and cichlid food. He is currently lying on his back or side, been alive for five days like that, we have been turning him over and he will start crawling to where ever as if he is ok ? He is not hiding anywhere any more? We don't know what is going on, Can you help? <Hello Sally. Usually when crustaceans aren't able to stand up properly, they're dying, or at least stressed. Start by checking water quality, and in particular consider if any copper could have got into the tank, e.g., from medication that was recently used. Do also check your dechlorinator neutralises copper that gets in via the pipes. Copper is very poisonous to crustaceans. Otherwise make sure water quality is good in all the usual regards: zero ammonia/nitrite, low nitrate, and in the case of crustaceans (and indeed Red Devils) that the hardness is nice and high and the pH well above 7.0. Crustaceans need additional iodine in the water, and the lack of it causes gradual, long term health problems. Iodine can be purchased as a simple supplement you add to the water, a bit like a medicine. It's sold primarily for marine tanks, so the place to buy it is from stores catering to reef keepers. Cheers, Neale.>

Crayfish comments, beh. 1/1/08 Every once in a while I review http://www.wetwebmedia.com/FWSubWebIndex/crayfishbehfaq.htm and find it very interesting, although the answers don't always reflect my experience. <Oh...?> I've had crayfish in a 50 gallon tank along with a community of tropical fish. Yes, they're territorial, but a good sized tank can be configured with all sorts of rocks and decorations that provide ample "territory" for a dozen or more crayfish. <Indeed. The problem is that many people who buy them stick them into 10 or 20 gallon tanks, and this approach doesn't work so well!> And they love to reproduce! The territorial neighborhoods only get over crowded when the number of large crayfish gets to me more than a couple. I also separate the female carrying a tail full of embryos into a smaller tank and raise the babies for a month or so until they're big enough to go back in the large tank without being eaten by the fish. Fifty tiny crayfish have no trouble finding or creating hiding places. As the population grows, you'll need to be releasing some of them back into your local creek or lake where they came from. <Ah, this may or not be legal depending on where you live. In the UK for example, releasing captive-bred crayfish into the wild is VERY DEFINITELY illegal. There is a major problem there because of fungal infections from American crayfish varieties having decimated native crayfish populations. Even releasing captive-bred offspring of locally-caught wild crayfish may be illegal in the US and elsewhere. While the crayfish themselves might not cause problems, they can carry ornamental fish diseases on their bodies, and these can spread to wild fish populations. Without exception, the responsible thing to do here is destroy unwanted offspring painlessly. In the meantime, do check your local Fish & Wildlife agency to see if what you are doing is safe, ethical, and legal.> Regarding their color, there are lots of variations within a new batch of babies: red, brown, blue. <Agreed.> A vegetable diet seems to shift colors reddish. A protein diet seems to shift towards a blue tint. <Interesting.> Of course, across the country there are hundreds of geographic variations that are beautiful. Almost black crayfish with furry claws are in Wyoming in the Teton National Park. Pale brown crayfish with bright orange claw tips are in the Rogue River in Oregon. Brown crayfish with a blue tint under their tail and white "elbow" bands on their claws are in the Sacramento river area of California, yet a few hundred feet away from the river you'll find the common all- red variety. I've not mated differing varieties to see what combinations are produced. <Are these "varieties" actually species?> I DO appreciate the website's comments about adding iodine! I was experiencing my largest (oldest) crayfish dying as they tried to molt without having a new shell. <Something new to me, too, but does seem to help!> Crayfish have personalities and provide hours upon hours of entertainment while observing them. <Agreed, these are wonderful pets. Do also look out for the giant Macrobrachium varieties like Macrobrachium rosenbergii occasionally sold as pets. These colossal shrimps are very impressive and I think you'd get a kick out of them. Cheers, Neale.>

Re: Crayfish comments 1/1/08 Thank you for the admonition/reminder about releasing "domestic" crayfish into the "wild." Since mine came from a nearby natural source, it didn't occur to me that they could become carriers of infection despite what appears to be their thriving. For the record, I've not released any. <Good. Do check with your local Fish & Wildlife Bureau. They may be fine about it, but it's best to check.> Regarding distinctive markings and colorations geographic variations, I picked up the "species" term from a government fish and wildlife employee who referred to them as different species when I talked to him about the variations. <Very good.> I've algae grow on the sunlight side of my small holding tank, the new fry seem to love it. <Yes they do! Most crayfish, and indeed most crustaceans, are at least in part omnivorous and appreciate plant matter and algae in their diet. When I kept land crabs, they went wild over ripe bananas!> Happy Gnu Ear! <And likewise, Neale.>

Lobster... FW Crayfish beh. 12/26/07 All right Bob Sorry to bother you, I have a couple of questions if you could please find time to answer I would be over the moon. I have a lobster/crayfish not sure what he is, anyway he seams to be a red colour but goes very blue when he is going to molt. is this in fact a sign that he is about to molt going bright blue? <Certainly sounds possible. Different crayfish change colours in different ways, so difficult to say for sure. Do watch diet issues; iodine is apparently one nutrient often lacking under aquarium conditions. Without the right diet, skeleton abnormalities are certainly possible.> Can I add other ones to the tank without them killing each other ? <No. Crayfish tend to be territorial. Even the ones that aren't will eat other specimens that are smaller/just moulted.> If you require pics let me know and I will provide. Thanks and I look forward to your reply happy new year S+F Scott <Cheers, Neale.>

Clawless Yabby; beh., fdg. 12/20/07 I am looking after an Australian Freshwater Yabby for a friend who is overseas. Two days ago, he escaped from his tank & fell off the kitchen bench onto the floor, & was found about 4 metres away from his tank. During this trauma he lost both of his claws. Once returned to the tank, he has been floating upside down, but still alive. My question is- if he stays alive, how do I feed him without his claws to grab the food? Or will he die? Any suggestions would be greatly appreciated. Kind Regards, Jodi O'Connell <This crustacean can, will consume foods of use still... really only uses the large claws for defense and seizing prey items... Maceration and manipulation are done via other smaller elements closer to the mouth. If this animal can be recovered, kept nourished, well-maintained, it will regenerate the larger claws with time, successive molts. Bob Fenner>

My freshwater blue crayfish seems to be eating its own antenna? Deficiency syndrome, reading 12/10/07 Dear WWM Crew: <Vilma> Thank you for your research suggestions, I followed them but I still did not find the answer to my question. I have a freshwater blue crayfish in a 10 gallon tank, my brother in law gave it to me for he could no longer house it with his fish species. I've had it for a little over 3 months and it seemed to be doing well until about 3 weeks ago when I started noticing that the long pair of antennas seem to have been shortened. <Good observation> The blue crayfish molted a few days after moving her into her new tank but has not molted ever since. <Also a good clue> Two weeks ago I did research online about crayfish eating their own antenna and all I found was that she might me iodine deficient <This and possibly biomineral, and/or alkalinity> so I added iodized table salt <Mmm, not a good manner to remedy> into the tank but I noticed that her antennas after the iodized salt treatment keep getting shorter. I don't think it's her diet, or water quality. <These are the most likely categories...> I have noticed a gray hue at the end of one of her antenna. Can you please tell me why her antennas keep getting shorter and what I can do about it? Thank you, Vilma Molina <Please go back and read on WWM re Crayfish husbandry, disease, nutrition, systems... Your pet lacks calcium, possibly magnesium... maybe in too high/low a pH/alkaline reserve situation... Some of this/these can be supplied through feeding... all posted. Bob Fenner>

Crayfish, beh. -- 10/9/07 I have a red 3 inch crayfish in a 75 gallon with a couple of other fish. He has just shed very recently. He has only been in the tank for two weeks now. Problem is when he shed he lost both his claws. I was wondering if this is normal. I was also wondering how long it will take for him to grow back his claws. There is no physical damage to him. <Greetings. Yes, this happens, and yes, the claws will grow back. With each successive moult, the replacement claws will get a little bigger. Within a year he should be back to normal (assuming a moult once every 4-6 weeks). Crayfish are easily damaged during the moulting phase, and being territorial and rather aggressive, they do fight and can pull one another's claws off. Ensuring all the crayfish have hiding places is important. Fish can also damage them. Finally, there's some anecdotal evidence that adding iodine to the water improves crayfish health. Be sure and read this FAQ, where Sabrina explains doses and uses: http://www.wetwebmedia.com/FWSubWebIndex/fwcrustfaq2.htm . Cheers, Neale>

My blue lobster/crayfish, fdg., beh. -- 9/29/07 Hi. I have a blue lobster/crayfish, which i brought some time in march. my lobster/crayfish was eating fine, until he/she shelled on Monday (24th September), now he/she just doesn't seemed interested in anything food what so ever. is there something wrong with my lobster/crayfish? any suggestions please. thanks. <Greetings. Crayfish tend to be extra-shy immediately after moulting. This is natural. For a couple of days their exoskeleton isn't strong enough to provide useful defence, so they stay hidden in their burrows. So give it a couple of days, and then see what happens. Do remember to vary the diet. Crayfish are primarily herbivores in the wild, and a lot of their diet is algae, soft plant matter, and decaying organic detritus. So you could try tempting your pet with something different. Sushi Nori would be ideal and especially rich in iodine, which crayfish apparently need for good health. You can pick this stuff up at any Asian food market or decent grocery store, and it's very cheap (over here in the UK, around £1 for 10 large sheets). Algae pellets (of the type sold for catfish) make a good alternative. Top this off with the other major part of the crayfish diet -- carrion. A nice bit of frozen whitebait or lancefish would be just the thing. The bones in these little fish would be a handy source of calcium. One last thing: crayfish, like most freshwater invertebrates, are sensitive to water quality. Check the nitrites are at zero and the nitrates fairly low. There must be no copper in the water (e.g., from fish medications) or salt. Not all species are tropical animals, so check which species you have, and if required adjust the temperature accordingly. Do also read this and its related articles: http://www.wetwebmedia.com/FWSubWebIndex/crayfishfaqs.htm . Cheers, Neale>

Crayfish molting-wow! 9/15/07 I don't have a question this time, more of an experience in awe. I got a 2" blue crayfish a month ago (discussed with Neale) and instead of putting him with fish as originally intended, his home became a 20 gal aquarium. The LFS said all their crayfish had been the same size for the few months they'd had them. I thought that odd they hadn't grown as they're supposed to get to at least 5" minimum. 2 wks after I got him I found his old shell where he'd molted. He'd been hiding in his log whereas he's normally very active but was eating very well. Thanks to Sabrina's insight I've added iodine since I've had him. The past 2 days he's been hiding again but still eating well. I just now looked into his tank and he's right smack in the middle of molting again! He's in his log but the log faces front and I have a perfect view with his fluorescent hood light. He's pulling off his shell as I type and his claws have doubled in size. This is the absolute coolest thing I've ever seen! He's super bright blue with pink tints and it's so pretty. He looks like he's doubled in size in just a month and I'm so happy to see my efforts have actually showed real results. Even though he seems to be molting a lot, I'm hoping that's only because he's 'catching up' and is healthy now. Just wanted to let you all know how excited I am-ha! Mitzi (& Master Slurp B) <Thank you for this endearing report! Bob Fenner>

Crayfish from Louisiana, beh. 8/10/07 Hi Nemo II, a crayfish acquired from a school project in Ottawa but originally from Louisiana, has claws that are turning fire engine red. Is it a sign of sickness or of molting? Thanks Lyndsay ( and her stepmom who really doesn't know what she is doing with this little creature!) <Hello Lyndsay. Nope, what you're observing is completely normal. Several species of crayfish develop coloured claws (technically: chelipeds) at maturity, presumably for social interactions. You likely have the species Procambarus clarkii though without a photo, I can't say for sure. Cheers, Neale>

Crawfish dragging claw 5/15/07 Greetings My daughter brought home a crawfish from school last September. He's been a happy healthy guy and a really good eater. Last week, he moulted and lost a claw at the same time. Problem now is his other claw is just dangling. <Something "missing" either nutritionally or water quality wise... for the "replacement" to be complete> He's dragging it along side of him. What, if anything, can I do to help him. <Improve both of the above... for "next time" it molts> It's breaking our hearts to see him like this. I find lots of information about claw loss, but nothing about a claw that wont drop off. Any suggestions please??? Thank you. Carol <Please read here: http://www.wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm and the linked files at bottom... on Systems, Health, Feeding. Bob Fenner>

Lethargic Red Claw Crab - 04/12/2007 Hi, <Hello.> I have a red claw crab, I keep him in a tank with land, fresh and salt water. <Excellent!> For the past two days he hasn't been moving a lot. (not that he does usually, but he seems like he has gotten somewhat stiff!) <Hmm.... Like he's.... moving more slowly when he moves? Or....?> I have been checking the heat if he is cold, but it hasn't changed a lot. <Do you have a thermometer to check the temperature? What is the temperature in the tank, and is it constant?> I have even been warming him up in my hand, but I don't think it's helping him. <That may actually be stressful to him, if he isn't accustomed to being handled.> I have had him for almost four months already, and I don't want to lose him. Please help!!! <If he hasn't molted yet, I would wager that that's what's happening (or about to happen). If he doesn't have a place to dig underground, try to give him a lot of nooks and crannies to hide in really well. Molting is a dangerous time in a crab's life, and they need to feel very safe and not be handled or messed around with. Try to make sure the temperature in the tank is warm (75-78F or thereabouts) and try to give him foods rich in iodine (shrimp tails, krill....). He may not eat for a few or several days, so remove any uneaten food. I should also say that he may not be molting; he might be sick. Unfortunately, there just isn't a lot we know, and really nothing we can do, about sick crabs. Mostly, the best things to do is provide them a perfect environment (you're doing great to give him fresh and saltwater, and land space), good nutrition, and help them to stay in good health. I hope he's just molting and growing though; that will be a sure sign that you're doing a great job for him. All the best to you and your crab, -Sabrina>

Electric blue lobster 2/6/07 My son has an electric blue lobster in his aquarium, and this morning it started molting. It stopped moving after it got a piece off the top of its head. <Likely a deficiency at play here... lack of biomineral, alkalinity, perhaps iodine> Now it isn't moving at all, and when I moved it a little with the net, I saw no movement. Is it dead, or is it still molting, and how can I tell? I do not want to leave it in the tank if it's expired, but I don't want to take him out if he might still be alive either. Thanks. <Please both of you read here, and soon: http://www.wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm and the linked files above. Bob Fenner>

Crayfish Molting - 10/21/2006 My crayfish is having a hard time molting. Can I help him? He is flipping himself upside down trying to crack his shell to molt. <Try adding Kent marine Iodine at a rate of one to two drops (NOT the marine dose printed on the label!) per ten gallons. This may aid him, but usually by the time that they are actually molting, it is too late to help much. Iodine should be added at this dose on a weekly basis.> Thank you. <All the best to you, -Sabrina> Shedding Crayfish 9/2/06 We acquired a crayfish about a year ago, who had been found in a box of books (which had been in storage for about 6 months to a year). We have no idea how he survived, where he came from or even what kind he is, other than he is bright red since beginning to molt. Yesterday morning (Thursday) he began to molt for the first time since we have had him and made it about half way, but as of this afternoon (Friday) the old shell is still stuck to the back half of him. He appears to be struggling to free himself every now and then. I am wondering if I should help him out in any way, or just leave him alone to do it himself? I know they stay hidden for couple of days after shedding, but how long does the actual molting process itself take? Any help or advice you can offer would be greatly appreciated. Thanks. Christy Schenher < The outer skeleton needs to become rehydrated and soften up. Give it some more time.-Chuck> Crayfish Climbing - 07/25/2006 Me again with a rather odd problem, <Hi again!> Vladimir, (Freshwater Crayfish) Has been trying to climb out of his tank. <.... and this is odd.... how? ....This is actually a very normal action, to be expected of Crays.... especially wild-caught Crays or ones that might prefer more space.> He will only do this in the middle of the night. We have 2 air driven corner filters for them. We do full water changes about every week, and try to keep the water as clean and clear as possible, yet he still tries to climb out. <Really, this is to be expected.> Would it be possible that Mavra (A female in the same tank as him but separated with a clear divider) is causing him to want to get to her, even if it means climbing out. <This is in fact possible.> We had a few close calls with him, he would constantly climb up the air tubing for the filters and almost completely out of the tank (15 gal) <A little on the small side for space for having only a small section (even if half) of the tank - I'd be climbing, too. This is a sufficiently sized tank to maintain their health, but they'd do a bit better in a larger system. Even that, though, may not put an end to the climbing.> We had to place a barrier over the top during the night to keep him from getting out and falling onto the ground. <A VERY necessary component of a crayfish aquarium.> On a better side, Mavra has molted and is closer in size to Vladimir, but at the same time Vladimir might be getting ready to molt also. I think this might make the gap slightly larger again. The other thing is, Vladimir is a lot more "thick" than Mavra, his body seems to be quite larger in mass than hers. She seems to be about 2/3 the thickness of him and I am afraid this would cause her to be damaged. <Yeah, I'd give 'em a bit more time.> Thanks for your time, -Colin <And thank you for your emails, Colin! I hope you will some day see baby crayfish from this pair! All the best to you, Vladimir, and Mavra, -Sabrina>

My crayfish lost all its legs on one side during the last molt. 7/24/06 <Mmm... something not right...> I was not home when it happened but I assume the fish took advantage of his poorly designed hiding place and weakened condition. <Likely...> This is his fourth molt in the past six months. <Pretty frequent... is this a small specimen?> What should I expect to happen now? If death is unavoidable is there a humane way to help? Thanks ~ <Might be able to molt yet again, regain some, all of its appendages... I would move this animal to another container, change its water out weekly with water from the present tank... keep offering small bits of food daily. Bob Fenner>

Crazy crawfish! Crawfish'¦.just being a crawfish 7/4/06 Yo! <Dude?!> First of all, I would like to thank Sabrina for her help with my guppy fry problems about 3 months ago. <She's even cooler in person.> They are doing quite well now (in fact, I had to give some away to prevent crowding), but I now have a new problem! <Uh-oh.> My female crawfish, Ashley, is about 5 inches long, and is completely obsessed with redecorating my aquarium! <'Tis quite normal.> I have a very well (artificially) planted 20 gallon tank, plus a rock cave that had formerly belonged to her (now taken over by my striped Raphael catfish, Chinese algae eater, and dojo loach). <Not the best idea to mix crayfish with these slower, bottom-dwelling fish.> Since he stole Ashley's cave, she has retreated to my forest of kelp-like plants. <Which if not anchored'¦.he/she will easily tear and un-root'¦very normal behavior.> All would be perfect except for the fact that she feels the need to move the plants to other locations. <Hehe, sorry to sound repetitive but it is really, really normal.> I have tried using plant anchors to weigh the down and keep them in the gravel, but she is just too big to be stopped. I have also tried to humor her and plant the plants in the locales of her choice, but she just moves them again, and all of this movement is beginning to stress my other fish out. Any suggestions? <None really, other than using only floating plants or a better anchoring system with larger gravel, perhaps another cave is in order?> Bonecutter <Adam J.> (P.S. My new guppies are beginning to do some sort of mating ritual or something. The males hover in front of the females and flare their fins out, then swim around them, then repeat. Are they mature enough to spawn already??) <How big/old are they? How long have they been in the tank'¦I say just be patient they are the rabbits of aquaria'¦>

Yabby/Crayfish, Age, Molting, Problems - 05/21/2006 G'day <Aloha.> I've read through quite a few of the questions and answers on your site and found them very useful. <Excellent!> Congratulations on such a comprehensive and informative site; I have a question of my own. <I hope I can help out.> Recently My Pet Yabby (Australian Cherax destructor) <A BEAUTIFUL species!> started to become very lethargic. As she had shed her shell several days before it did not concern me too much. <Mm, it is actually disconcerting that the animal be lethargic for this long after shedding....> However it became become worse over the last few days and she kept falling over onto her side and curling her tail in, and then struggling to get back onto her legs. I had the water tested for by the local aquarium, and they concluded that minerals water quality and pH levels were as they should be. <Hopefully you were able to verify this yourself, as well.... It's best if you test the water yourself, too.> However the condition got worse so I made water changes, and tried adding a small amount of Sodium Bicarbonate but this still didn't help. I also tried aerating the water more. Eventually it got to the point that my Yabby could no longer roll back onto her feet without help, and I lost her to Yabby heaven. <Yikes. I'm sorry to hear this.> Can you please suggest anything that may have caused this? <Lack of iodine in the water, perhaps....> As I now have a new Yabby and would like to avoid any repeat. Could she have died of old age? I've kept her for at least 6 years happily and healthily without ever having a problem. <Six years? Yeah, I'd say "old age" may be the ticket. She had a long life with you.> Suggested lifespan is 3-5 years... Also about 4 weeks ago I moved house and had gotten my Yabby a larger tank (30 litre). So could the change of environment have something to do with this as well? <Possibly, but again, it may have just been her time to go.> Although she seemed to love her new tank and was quite lively before she shed her shell. I was feeding her Yabby and crayfish pellets (including fish and kelp meal), vegetables, and the occasional Lucerne pellet, all of which I've fed her for the 6 years. I did notice that there was a piece of uneaten broccoli that I missed, which would've been there for several days, could this have poisoned her? <Only if it had begun to rot and there was measurable ammonia in the tank.... I'll hazard a guess here and say that there was likely not much you could have done to prevent her passing.> Any advice your team could give me would be much appreciated. Thank you for your time, and also for providing such a useful and informative site. <Thank you for your kind words. I do wish you the best with your next Yabby pet.> Crystal, Victoria Australia <-Sabrina, currently in Hawai'i, USA, but usually in California.>

Colin's Concerns About His Crayfish - 05/21/2006 Dear WWM crew, Yeah, it is me again. <Heh, no worries.> I am sorry for having to send another email but I need a little more advice. <I hope we can be of service!> I searched for crayfish molting but haven't found much pertaining to my problem. Vlad, my larger crayfish seems to be molting. He seems a lot more sluggish as of lately. He also appears to be turning a whitish color from his usual brown. <Not a good sign....> Also lately he has been going under the slate ramp to the "upper deck area" and tilting himself to an almost 90 degree angle on his side. <BAD sign....> Is this normal? <No.> Should I be worried? <Yes.> I really love my little Vlad and I hope he is ok. If he is molting and leaves his shell off do you think I should try leaving it in and seeing if he decides to eat it? <Only for a day or so.> Thanks for the help, I really appreciate it. <Please consider doing a water change, urgently, and adding a bit of iodine - the kind sold for saltwater/reef aquariums. Don't use the marine dose printed on the bottle, though; just a drop or two per ten gallons will do. Offer him foods like freeze-dried krill and shrimp. Hopefully these things will help him out with his molting. Wishing you and Vlad the very best, -Sabrina> Shy Crayfish - 05/16/2006 I brought a blue crawfish home from Louisiana several days ago. It's in a tank with pond water, alone, but is burrowed into a fake hollow log I put in. Will she ever come out? <Yeah, probably. Pay close attention to water quality, give her meaty foods like bits or tails from frozen/thawed human-consumption shrimp, and she'll probably do just fine. If you're not familiar with these topics, please do read on WWM regarding water quality, tank maintenance.... Wishing you and your new Cray well, -Sabrina>

Yabbies Hello, We have some red claw yabbies in a tank. One is a female and she has been carrying eggs under her tail for about 7 weeks. They have just hatched and I noticed her in her pipe lying on her side motionless. She appears to be molting because her body seems to be breaking out of her shell. She was moving around well last night. My question is how long does the molting process take is it hours or days? I must admit she doesn't look healthy, but then I suppose losing your shell would be a hard task. I would appreciate your input because I can't seem to find anything of the Internet about it. Regards Kim <Hi Kim, the last time one of my crawfish molted it was over matter of days, it stayed secluded for a while, then I found bits and pieces of shell everywhere, I thought he had been munched. Then a couple days later, he was back. After they molt they like to stay secluded while their new exoskeleton hardens. They are vulnerable to cannibalism while they are still soft. The article below may provide you with some more info. Best Regards, Gage http://216.239.57.104/search?q=cache:E_IVJdpNrGMJ:aquanic.org/publicat/usda_rac/efs/srac/244fs.pdf+yabbie+molting&hl=en&ie=UTF-8 >

Blue Water Lobster Dear Bob <Hey there - I'm not Bob, but I am the freshwater invert-obsessed Sabrina - hope I can shed some light on your new critter.> We have a Blue fresh water Lobster but are having a few tiny problems with him/her and wonder if you may have any answers? <Hmm.... I've seen a few different animals that fall under this name, any of which might be the critter you've got. It could be any of a handful of Procambarus species (crayfish) that is blue or has a blue form; or could be either of two blue Macrobrachium shrimp species - M. rosenbergii from Thailand or another species from Mexico. A picture would go a long way to identifying it, if you've got one.> He is attacking the big Plec and ripping the Pleco's fins. He has also started recently to kill the smaller fish by grabbing them with his claws. <For any of the species above, this is quite normal.... they don't play well with fish.> Is there any way we can stop this? <No, not really. Separating him from the fish is pretty much the only way to end the carnage.> We have now put in a ceramic pot and cave entrance to give him a safe cover, will this help combat the problem? <No, unfortunately. Regardless of which of the above critters it is - they're aggressive, and fish-hungry.> We feed him on prawns <Excellent food for 'em> and specially bought crab cuisine which states is ok for Lobsters. Should we be feeding him anything else? <Ocean Nutrition's frozen Formula One is a good food choice.> We have looked everywhere for a book on Lobsters but have had no luck. <Do some google searches on 'blue crayfish' and 'blue prawn', as well as the above Latin names.> He is now about 4 inches long without counting the claws. <And will grow about twice that> He is shedding about every three to four months and eats his shell afterwards. We have had him now for ten months and has shed three times. He is showing signs of being due for another shed as he is constantly laying on his side and acting as though he is dead, which we have noticed he does this just prior to shedding in the past. <I don't think that's a good sign.... perhaps try adding iodine to the tank (use Kent's marine Iodine supplement); one drop per ten gallons every week.> He is constantly shoveling the stones about, we have had to change from a sand bottom as he kept blocking the filter with the constant moving of the sand. We now have an undergravel filter. If you have any information that will help our Lobster Rocky to have a good life, would you please be so kind and inform us? <I am sorry for the news that he'll be always incompatible with most fish; he may warrant a tank of his own. There are a few fish compatible with these animals; do some google searches to try to find out exactly what you've got, and hopefully that'll help you out some. Wishing you well, -Sabrina> Thank you in anticipation. Yours sincerely Mr. John Edwards

Yabby Lifespan hey fellas I was wondering how long a Yabby lives for???? thanks <About three years. Bob Fenner> Worried about my blue lobster! I bought my blue lobster not even a month ago. She was very active, ate well (plankton cubes, blood worms so far.) She even ate a goldfish the night I bought her. Here's the problem, I fought the lobster on its back, and looked dead. I water sample was a high PH. The tank was warm and big enough. I cleaned the tank, corrected the water issue, and periodically check the water, put the goldfish in a separate tank, so the lobster is by itself. She came around again, to her normal self. About 5 days later she's on her back again. I understand this is molting I think, I can see the shell lifting off her. My question is, how long does the molting last, <Usually only minutes to a couple hours> is she dying? She's been upside down for 24 hrs. BUT when I moved her little house, she moved? I got a bad feeling about this. But do lobsters all have a different style to their molting? PLEASE HELP! thanks, from Kay in Ohio <May be that your water is too soft... do you have readings for pH, alkalinity? Do you supplement iodine/ide? Bob Fenner>

Crayfish behaviour After one of my smaller crayfish died (yes I was very sad) I thought they may have lacked in oxygen. I didn't have a pump. (Could this have been the reason?) <Yes... or consequences thereof... e.g. no filtration> So I purchased a pump. It saves me from changing some of the water as often anyway. But I've noticed all they do is climb on the pump and what appears to be eating bubbles from the pump. I have a lid so they can't get out but they also like to climb up and rest completely outside the water. Is this normal behaviour? <Sounds like this is so... perhaps this is a species that needs shallower water, or even to emerse itself at times. You might try to find out specifically what you have, use the Net search tools to determine its natural history. Bob Fenner> Sometimes they hang there for a good hour. Thanks for your help. Daniel Crawdad with no pincers... Hello! I just saw my crawdad molt for the first time, and I have a question or two. I never even knew they molted, actually, but it does kind of make sense when you think about it. <Yep, have to molt to grow...> Anyway, my crawdad, Nixon (so named because when I first got him, he'd run around the tank with his claws open a la "I'm not a crook"), now has no pincers due to his molt... I've had him for at *least* three years, and he lost one claw in a battle with another, rather temporary, crawdad. Since then, he'd been doing fine with just one claw. But now I'm worried. He's about 6 inches long, and I'd never seen him molt before. I found all the pieces to his old shell, including his one and only claw. Will he be able to eat, and will the claw grow back? <Mmm, a couple things to impart to you... one, do leave the old exoskeleton in the tank... or put it back if you've removed it... "Tricky Dicky" can/will reincorporate this into its new outside... and do read on WWM re Crayfish keeping... they need adequate nutrition, sometimes iodine/ide additions, hard, alkaline water to grow, successfully molt... And will regenerate limbs if so kept> His other claw never did. Why did he lose the claw at all, was it a bad molt? <More likely insufficiencies in its system, feeding> He lives in a 30 gallon "pond" with three goldfish, about a bazillion snails, and lots of green mossy stuff that I think is called "bloodwort". I'm not worried that the goldfish will get him or anything, but I just wonder if he'll be able to function normally (i.e., can he still move rocks or get food?) . He's just a local creek crawdad, no special pedigree or anything. Thanks for any help! ~Ida <Please read here: http://www.wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm and the linked files on the bottom. Bob Fenner>

Crayfish page? I'm sorry I'm such a dork, I'm looking for a way to post a question on the crayfish page. My son caught a crayfish and wants to keep it for a week then return it to the creek. We made a tank with pond water and rocks. Now the crayfish stands on top of the rock with his back out of the water. We are wondering if he is going to die soon. My son is in Second Grade and is taking this pretty hard. Thanks for your help. Chad <Actually "crawdads" are pretty tough... and some are amphibious! Yours should be fine. Bob Fenner>

Re: crayfish page? Bob <Chad> He made it through the night just fine. Thanks for your help. <Ahh, good to hear, read. BobF> Chad

My crayfish... 1/16/06 I have an electric blue crayfish I bought from the pet store about 2 months ago. Chomper is about 3 and a half inches long. She eats blood worms, Hikari crab pellets and the odd fish flake if she is still hungry. She has been a big eater since she came home. She shares a 20 gallon freshwater tank with 2 rainbow fish. There are live floating plants (were rooted but thanks to her they are not anymore), <Know what you mean> there are plenty of hiding spaces and gravel / sand for her to borrow in, filtration and aeration systems. The water levels and temperature are all normal. All was fine until 2 weeks ago. Her shell started turning brown with white dots. Her pinchers are still blue. Now she has a velvet growing on her joints and on the tip of her nose - I don't think that is what it is called, but it sticks out. She still runs around the tank and eats as normal but why is this happening and how can I fix / prevent this from happening again. <Mmm, I do hope this is not pathogenic... that is, caused by an infectious or parasitic agent... but from water quality, perhaps a missing nutrient> As far as I know she has not molted since she came here. She doesn't hide often and if she does she is out and about shortly after. I've tried taking pictures of her but as soon as she sees the camera she runs... everything I can find relates to worms and they don't look like that. Any information would be a great help. Thanks <Have you read Gage's Crayfish article and the Related FAQs on WWM? Please do. Bob Fenner>

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