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Crayfish, Crawdads, Yabbies, Ditch Bugs Disease/Health 1

FAQs on Crayfish Disease: Crayfish Health 2, Crayfish Health 3, Crayfish Health 4, Crayfish Health 5,
FAQs on Crayfish Disease by Category: Diagnosis, Environmental, Nutritional, Trauma, Infectious, Parasitic, Social,

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 Behavior, Crayfish Compatibility, Crayfish Selection, Crayfish Systems, Crayfish Feeding, Crayfish Reproduction, Freshwater Invertebrates/Use in Aquariums, Freshwater Crustaceans for the Aquarium, FW Crustaceans 2, Fresh to Brackish Water Crabs, Hermit Crabs,

lack of appetite and eye changed color, data/reading 9/11/10
I have a leucistic (or white) male crayfish that I bought from a local pet store and I have had him approx. a year and 4 months. During the first 2 - 4 months, I owned him, he molted twice but has not molted since.
<Indicative of? A lack of nutrition, insufficiency syndrome... iodide lack?>

He has gone at least a full year without molting and is very small being only a little over 3 inches from the tip of his pinchers to the end of his tail. I assumed the reason he is not molting is because I have not seen him eat anything in several months.
<Very bad>
During the first 6 months I owned him he would eat shrimp pellets or algae wafers without any problem but he was never a big eater. But for the past 6 months or so, I have not seen him eat anything. In addition to the pellets
and algae wafers, I have offered him lettuce, peas, zucchini, carrots, etc. not only does he not eat but he also shows no interest in the food at all. I will drop the food near him and he never even moves to investigate it.
At this point, I really do not know how he is surviving. I have been sporadically putting 1 drop of marine iodine
<Ah good>
in his tank too but I read that I should probably be putting it in about once a week, which I will start doing if you recommend it.
<I do>
Then last night I noticed that one of his eyes had turned brown and I have attached a picture of this in my email.
Despite these things, he has been acting the same as he always had. He is not lethargic or sickly. He will come out and walk around the tank every now and then and he even recently mated with my female Electric Blue Cray.
I am still extremely concerned over his lack of appetite and over his eye changing color and I am not sure how to help him. Any information on this would be appreciated. Thank you.
<What re water quality, maintenance...? Read here:
and the linked files above. Bob Fenner>

Crayfish, death... from? - 8/10/10
I didn't see anything that matched what I'm wondering. If there is I'm sorry. I've had my crayfish for about 4 months. And it has molted once. And about 5 days ago it stopped eating and went into hiding. I thought it was molting again but this morning, I found it laying on it side dead in the middle of the tank. Do u know how this may have happen? I feed it shrimp pellets, And change its water often, has a good filter that filters for 10 more gallons of water than is in the tank.
<Hello. It's reasonably well established now that crayfish need the use of iodine in the water. Buy the stuff used in marine tanks as a supplement, but use at about 50% the quoted dose. If used regularly as instructed on the package you should find crayfish moult successfully and live healthy lives. Cheers, Neale.>

my blue yabbie... hlth./env. - 6/12/10
Hi I have a blue yabbie, I live in Australia. It has developed a large brown spot and lost both his claws. He used to be so active and has been in hiding for about two months, he has lost his appetite and does not seem to want to eat. He used to be so active , he is in a 20 litre tank and he is the only yabbie in there as he ate all the fish . He used to be really aggressive and it seems like he now has depression and is in permanent hiding. Can you please tell me what might be wrong
<Hello Veronica. It's almost certainly poor environmental conditions that are to blame. 20 litres isn't enough space for anything but the smallest crayfish, so if your chap has a body length above, say, 5 cm, he really needs a bigger home. Filtration is essential, not optional, and diet should be based primarily on green foods, not fish. Do read about the needs of these animals, and pay attention to water quality, water chemistry and the use of iodine supplements.
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.
Cheers, Neale.>

Crawfish Question 1/14/10
I need your advice please. A week ago I purchased 6 regular crawfish from a pet store. The store owner also talked me into buying two additional ones what he called a "crimson" and a "Blue Lobster". I ordered them the day before they were delivered to the store.
First what he called a crimson I found out after looking him up on the net is a Procambarus clarkii. He is considerably larger then all the other crawfish.
<Oh! I did a "senior report" in Ecology on this species in college! A substrate size preference study... P. clarkii has been spread over a good deal of the U.S.... is quite common (though invasive) in California where I live>
The "Blue Lobster" is very small in size and I really couldn't find a species called "Blue Lobster". I have the Blue guy in a separate tank.
<Mmm... please see here:
some species are predominantly blue, but can/do change with molts, nutrition, water quality...>
Of the six regular crawfish I purchased two are "Reddish" in color, Two are Brown with the fatter kind of claws and two are a very light gray, almost white or see through.
I have the Clarkii and the other 6 in a 10 gallon tank with the 2 previous crawfish I had before them.
<Yikes! Are predaceous... will eat each other...>

After about three days home with them, I started to notice some white-like- mold growing on the end of the Clarkii's tail. Soon there after, I noticed that one of the Brown ones has some white bumps on it, like tiny granules of salt sticking to the side of it's head. Today I saw that one of the Reddish ones that has these salt like things on top of his head and a Brown one has them growing down his side too.
<Could be... Please read here:
Is this the WSSV I have been reading about?
<Mmm, White Spot Syndrome Virus... maybe>
I could not find a picture of what this looks like. I tired to take pictures of mine, both in and out of the tank tonight but for some reason my camera just will NOT take a clear picture of them, always comes out blurry. Just the crawfish everything else in the background is always in focus.
<Need either another camera or to see/check if this one has a "close up" setting (look for a symbol that looks like a tulip)>
Tonight one of the Reddish ones with these growths (a male) mated with a brown one (female) that has no signs of this growth.
I bought these six originally to try and get them to have babies because one of my original four had 12 this past November and they were all eaten either by the other three of the feeder gold fish I keep in the tank with them.
So now that you have the story what I would like your advice about is:
.Should I return just the infected crawfish to the store as I have a 14 day guarantee on them?
<I would return them all>
.Or do I return all of them?
.Should I keep them. Does this stuff just keep spreading and will it hurt the feeder fish in the tank?
<The Procambarus will likely try to eat the goldfish...>

From what I read if this is WSSV there is no cure for it yet. By the way the blue on is in a separate tank and shows no sign of this problem either.
Confused In Iowa
<Read a bit first... try sending along a good image or two; then decide what you want to do. Bob Fenner>

Crawdads pinchers 11/11/09
My crawdad is five years old. He was molting and his pinchers got caught in the old and I had to help him. However, he was caught for about seven hours cause I thought he would eventually get them off. Now that they are free, his pinchers are upside down and he stays on his back. It's freaky.
If I cut his pincher/pinchers off at the base, will he still live? help!
<I wouldn't pull the pincers (not pinchers!) off since that requires a great deal of force, and you're likely to damage the crayfish in the process. It would certainly be very traumatic for the animal. Much better to let nature take its course here. Do note that many "failed" moults come down to insufficient iodine, and for freshwater crabs and crayfish, supplying iodine really makes a big different in terms of success. Some crustacean-specific pellet foods may cover this aspect of things, but otherwise use a standard marine aquarium iodine supplement at about half the quoted dose. Cheers, Neale.>

Found a crawdad in our backyard 6/18/2009
Hi my name is Deanne I live by Castaic Lake. Today my daughter found a crawdad in our backyard, and we have no clue as to how it could of gotten there.
<Most often carried/dropped by dogs, cats, raccoons, birds, and so on.>
We had Terminex come and spray for pesticide yesterday, and Im afraid it might of ingested some of it.
<May well have done, or else simply damaged or stressed by being carried and dropped out of water.>
He was still alive when we found it, but moved it a couple time not sure where to put it. We finally decided that the fish tank was the best place for it. It seemed to be doing fine, moving around etc, but after a while it kinda just fell over onto its side and hasn't moved since. Nothing but a few leg twitches and a claw closing but tats it, is there anything we can do for the poor thing?
<Probably very little; by all means improve circulation and oxygenation, and ideally provide water that isn't too warm if this you live in a temperate zone area rather than the tropics. Observe, and if the thing dies, do remove the body quickly.>
Thank you
<Good luck, Neale.>

Question concerning Crayfish. -- 06/15/09
Hello there, names Josh. I've been searching the internet for a while now and have yet to come across the information that I am after.
Though your site is quite informative and I've picked up a few bits of info that will help.
Right so I'll fill you in with a bit of background info first: I've had the tank for about 3 months now, it's a 60 litre (15ish gallons?) tank and my first addition to it was 2 crayfish, which I believe are Red Claw crayfish
but im not 100% on that.
<A bit small for Crayfish and fish; do bear in mind Crayfish are opportunistic, and they'll view small fish as potential food.>
Shortly after I added several fish including some different types of tetras, a couple of bronze Corydoras, a Plec (who is growing extremely fast), a male and female fighting fish and recently a couple of guppies.
<None of these are viable in 60 litres. A Plec will need something upwards of 200 litres, Corydoras should be kept in groups of 5+ specimens in tanks 90 litres upwards, and Guppies also need a lot of space, say 90 litres, because the males are very aggressive towards each other and the females. A male Betta is simply Crayfish food, being so slow and easily captured, and in small tanks, male Bettas do tend to harass female Bettas.>
I've lost a few of the tetras and a guppy which im not too bothered about, as when I bought them I expected a few of them to get caught, I guess its good for the crayfish's diet to have some live food available (which has become pretty much impossible to acquire with a lot of new laws coming in in England about live bait....).
<The English laws are about animal cruelty, and sticking animals together and not caring if some of them get eaten is irresponsible, whether or not you personally view it as cruel! These laws don't stop the trade in live
river shrimps, bloodworms and other invertebrates, but yes, most retailers have taken these laws to mean the use of feeder fish is prohibited. It isn't clear that's true in point of fact, though doubtless someone could
make a case and set a precedent. That American hobbyists use feeder fish isn't an advantage; Bob has long argued that feeder fish are a major cause of mortality to things like Lionfish, and recent work on Thiaminase has clearly demonstrated that Goldfish and Minnows are highly inappropriate foods for predatory fish. So unless you're breeding and gut-loading your own livebearers or killifish, there's no safe way to use feeder fish, and moreover, most predatory fish don't need them anyway. Besides, crayfish are largely herbivores/detritivores anyway, so there's no need to give them live fish as food. Algae wafers or their equivalents make excellent staples, augmented with occasional offerings of meaty foods such as small
pieces of krill and lancefish now and again. Do see here:
The crayfish are around 4-5" now and are about to moult again. Their diet includes sinking pellets named "Crab Cuisine", flakes of fish food that the fish don't get, live plants, and frozen food such as brine shrimp and bloodworm.
Okay so here's my query: Since I've bought them I've been noticing that they have these strange white worms on them, they are usually around the front of their face, near the eyes and the shorter antennae/feeler things they have.
<Harmless commensals.>
But they do move around the body as well... At first i thought they might be somewhat beneficial to the crayfish cleaning them and stuff but I thought it best to check as when I was searching the internet I came across an un-answered question where someone's crayfish was found dead with "loads of white worm things crawling out of it".
<Not a threat as such.>
Also I was wondering if you could provide me with or point me in the direction a DETAILED list of food (household vegetables and meats) that the crayfish can eat because I don't want to be putting something in there that will be harmful to them.
<See above, and stop feeding them live fish.>
Thanks a bunch for your time and I'm sorry if you've already answered a similar query and I've overlooked it. :)
<Cheers, Neale.>

Is our crayfish dying? More reading 05/23/09
My son just got a Cray fish from school and it moulted today (our first time). After reading the other answers, I still have questions. Ours is not hiding.
<Unusual... a "normal" behavior... to guard against predation...>
She is lying on her side and does look exhausted. Can she stay lying on her side for very long? And how will we know if she is dying and not just resting, so we can put her out of her misery?
<Mmm, keep reading... re the needs of these animals... Your water quality may well be deficient in Ca, Mg... and I2 supplementation may well help here... Too much to reiterate... but is all posted. Bob Fenner>

Blue Crayfish with Terrible Wound 05/21/09
My crayfish has developed a terrible wound on the left side joint on the claw/arm. It is a brown rustic color in the center with a slight white ring around the edge.
1. I am embarrassed to even post the attached photo as it looks even worse out of the water.
2. I was hoping to help this problem by increasing water changes and adding a little salt.
3. It has progressively gotten worse over the past month or two?
4. Can I cure this without killing the rest of my fish (Gromies / Cat Fish) in the tank?
Thank you for your help!
<I'm not an expert on treating infections in crustacea, but I'll give a shot at clarifying this. Hopefully someone will see this who has dealt with it before to help you.>
<It looks like the claw is hanging limp in the photo, has the crayfish lost use of the appendage? This would indicate that the problem is internal, not external. Also, is the rust colored substance in the suture (space between hardened plates, or sclerites) a surface gunk or powder that comes off, or is it a sub-surface discoloration? If we can determine the location and bacteria/fungus question for this we can start looking at ways to treat it. It sounds chronic and not acute, so I'm willing to bet we have some time to deal with this.>
Kind Regards,
<Hope your clawed friend is holding in there>

Blue Crayfish with Terrible Wound 05/23/09
My crayfish has developed a terrible wound on the left side joint on the claw/arm. It is a brown rustic color in the center with a slight white ring around the edge.
<Wow... good pic, bad injury>
1. I am embarrassed to even post the attached photo as it looks even worse out of the water.
2. I was hoping to help this problem by increasing water changes and adding a little salt.
<Mmm, no>
3. It has progressively gotten worse over the past month or two?
<From... ongoing microbial/bacterial decomposition? Perhaps a lack of essential nutrient, water quality...?>
4. Can I cure this without killing the rest of my fish (Gromies / Cat Fish) in the tank?
<Likely so>
Thank you for your help!
Kind Regards,
<? Where's the rest of the info? Re the system, history of set-up, maintenance, foods/feeding, water quality test results? Am too limited by Net access where I am presently to look up for you, but just read on WWM (the search tool, indices) re Crayfish period... Very likely the best course of "action" here is to assure complete nutrition, adequate biomineral and alkalinity content in the water... a bit of iodide/ate supplementation, and time going by... to promote moulting... healing of the wound site, replacement of exoskeleton and tissue. Bob Fenner>

<<Nice pic! -Sara M.>>

Sick Electric Blue Lobster? 5/18/09
Hi, we purchased an Electric Blue Lobster about 6 months ago. First he was in a rather large tank but he ended up eating most of our fish
<Not uncommon... despite being herbivores in the wild, Crayfish are notoriously opportunistic!>

in there so almost a month ago I moved him to his own 10 gallon tank. He'd been doing fine until about a week ago we noticed what we thought were his gills under his thorax turning red, well this has multiplied exponentially over the last week and the entire underside of his thorax is swollen to where it looks like there is something growing on him and bright red.
<Is this something growing on the carapace, or is the carapace actually swelling up and looking inflamed? Epistylis is a fairly common "disease", being a type of protozoan that forms fluffy white to grey scum across the carapace. It's harmless in itself, merely using the Crayfish as a place to grow. Temnocephala is something similar, a kind of flatworm that multiply (and move) across the carapace. Again, they're harmless, though unsightly.
More serious are moulds such as the Crayfish Plague (Aphanomyces), a fungus that forms dark threads and clots in the muscle, most obviously on the underside of the animal, especially on the abdominal and leg segments. It can't really be cured, though some Crayfish are resistant (e.g., the Signal Crayfish) while others are killed quickly (e.g., European Crayfish). There are an assortment of other diseases to which Crayfish are subject, but there's little/nothing about these in the hobby literature. As with many invertebrates, "prevention is better than cure".>
We thought maybe it is actually a female with eggs, but we've had it a long time and never with any other lobster's and the red "growth's" have some white "fuzzy" stuff on them as well. I looked through the site but nothing seemed to resemble what we are experiencing here. I did check the PH and Ammonia and they are okay. He hasn't molted either since we got him, could he be molting?
<Or perhaps a stalled moult; do review the need for [a] a source of calcium, such as whole shrimp; and [b] iodine, via the addition of marine aquarium iodine drops and one-half the stated dose. In addition, the diet should be algae-rich; Spirulina wafers are good. Some crustacean-specific foods are on the market, and recommended. Do read here for more:
Stalled/failed moults are very common among crayfish not given the right diet/iodine supplement.>
Any help would be appreciated, we really don't want to lose him.
<Good luck, Neale.>

Electric blue crayfish, hlth., moulting, I2 5/12/09
Hello I have a question about giving my crayfish Iodine. I just bought some iodine for my crayfish and it says for every 50 gallons use one drop. I have a 20 gallon with 2 crayfish in it will this harm them from being to much
<There is such a thing as overdosing of this halogen... but there is a rather large range of efficacy... given the types of common interaction with many "tap"/source waters... and biomass... You will not have a problem with only administering the one drop... per... interval of when you do regular water changes (likely no more frequently than weekly)>
Or will my carbon and poly filter suck most of it out?
<Yes it will, would...>
Should I leave the carbon an poly filter out when I do put the iodine in?
<Yes I would>
If I do how long should I leave them out?
<A day>
I have been feeding them beef heart, algae wafers, tropical flakes, and a pellet for carnivores such as the red tailed cat. Is this food ok or is there something else that is better?
<These are fine... the beef heart can be messy though>
They have molted twice in my tank the first time was perfect the second is what has me worried. One of them is still a light pink and a bit soft still and it has been 4 days.
<I'd be reading, testing for alkalinity, perhaps biomineral (Ca, Mg) content in your water... maybe adjusting/supplementing for such if these are deficient. Please read here re: http://wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm
and elsewhere (use the search tool) on WWM re the chemicals, properties listed>
So the iodine is the only thing I can think of to help her. Please and thank you for your help.
<Mmm, w/o the water conditions noted, moults can be seriously hindered as well... Some folks have water that is too soft, otherwise lacking in alkaline earth materials, to successfully keep Crayfish. Bob Fenner>

Cray fish worms, just using/reading WWM 5/12/09
I have had many crayfish over the years. Gimpyshrimp<his name was missing 3 legs and a pincher>
<Mmm... Crays should regenerate these in subsequent molts... see WWM re their health>
has the worms/parasites that come out by his eves, top of head, thorax, and every overlay of his shell.
<This is also covered>
This is the only crayfish that I have noticed them. I got 2 really good pictures of the worms on him. They need to be magnified 4x on my 4 meg camera. If you would like to see them write me back at XXXX my girlfriend will have to show me how. I am not good on the comp., just learning. I never saw one molt until I watched it on your site thanks very much
<Please read here: http://wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm
and the linked files above. Bob Fenner>

Is out crayfish dead? 4/21/09
Hello and thank you for your help.
My daughter brought home a crayfish from school about 4 months ago.
We found him upside down in his tank last night.
Her teacher said he might be molting (said that they look lifeless during this time).
<No, they don't really become lifeless, rather retiring, and hide away in their burrow. But apart from that, they're much like normal. His gills should be moving, his antennae twitching, and so on.>
He is on his side this morning and I see absolutely no movement of any kind.
<His metabolic processes are now history! He's off the twig! He's kicked the bucket, he's shuffled off his mortal coil, run down the curtain and joined the bleeding choir invisible!>
How long does it take to molt? (I did notice a crack where his tail meets his body.)
<Depends, best part of a day really.>
Could something have gone wrong during his molt?
<Yes; iodine drops, at half the dose used in marine tanks, seems to be critical. Do see here:
I don't want to dispose of the poor little guy if he really isn't dead.
<Indeed not.>
Thanks again for your help.
<Cheers, Neale.>

Turning brown with white spots on claws 4-13-09
I have an electric blue crawfish and he is getting more of a brown fuzz around his back, head, and pincers. He is also getting white spots on his claws. Could this be because of a stressed environment around him? He constantly tries to climb up the aquarium walls and also seems to be trying to clean his back with one of his little claws. I keep him in a 10 gallon tank with two artificial items where he can hide and climb on, but there are no plants or anything.
Thank you
<Hi Brandon. I need more information that this. In particular, tell me about the pH and carbonate (not general) hardness. These are the two critical factors with Crayfish. Like other animals with shells, in water
that is acidic or has a low carbonate hardness, they have problems making their shells. Over time the shell can become pitted if the pH is below 7.0, and these pits can become focal points for growths of algae. In the bigger picture, when the Crayfish gets ready to moult, it will have problems building its new exoskeleton. I'd also make the point that Crayfish are primarily herbivorous in the wild, so should have access to plant material of some sort. Some folks make the mistake of giving them feeder fish and the like, and nothing could be further away from what they actually need.
Plant foods such as soft vegetables, Nori and algae wafers should predominate, augmented once a week with calcium-rich animal foods such as an unshelled prawn or a whole lancefish (for the bones). Do read here:
Cheers, Neale.>

Blue Lobster Ill, likely stalled ecdysis/env. issue, reading 4/4/09
I have a ten gallon FW tank with a blue lobster, scientific name unknown.
<... See WWM re>
All water parameters are in normal range with nitrates around 25ppm.
<Too high>

He has been happy and healthy with me for two years although his diet has probably consisted of to
high of a ratio of meat to plant material. Recently, within the past week he has developed a sore on his back that has a white pustule in the middle of it. The area surrounding the pustule is red and is spreading.
The best comparison I could give is a pimple that has come to a head. I tried to remove the white center with tweezers, with no success. At first this growth and redness seemed not to affect him. Now though his appetite is decreasing and he is becoming lethargic.
<... alkalinity? Biomineral content, measure?>
Are you familiar with any parasite or illness that could cause this growth and the accompanying symptoms and or could he simply be reaching the end of his lifespan? Any insight would be appreciated. Thank-you
<... Read here: http://wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm
and the linked files above.
Bob Fenner>
Re: Blue Lobster Ill 4/5/09

I am just a little confused. I wrote in hopes of finding some answers for my blue crawfish. He has developed a sore on his back that is growing larger and I wanted to know if anyone has any idea what it could be and if it could be treated. I got an email back informing me to read the disease facts page for this species. However I already scoured these pages. Was this a suggestion that he has crawfish plague, or a bad molt, or a deficiency,
<This... my best guess from the data proffered is that you have a lack of biomineral content>
the sore he has is most definitely not the worms that others have written in about. The white center of the sore is inanimate and I have tried to tweeze it out. However his health is becoming worse and I had hoped for some kind of direction because I found nothing promising in the information already posted. If anyone could let me know if they have seen sores like this before and if it alone could be affecting his health and causing his illness.
<... again, you need tests for Calcium, perhaps Magnesium, overall dKH... Iodine...
"White Spot Disease" Not Ick... more Blue crawfish with no new data... 4/5/09

I have written in a couple of times now trying to discover what is happening to my blue crawfish. I was basically told to read over the facts on the website, which I did but the discovery of this "white spot disease" in invertebrates seems to most closely resemble his condition.
<Is not this... the very name specifies fishes>
I have a final question about the illness that my crawfish is suffering.
I have been researching it on the web and I am wondering if my crawfish could have "white spot disease"
<Assuredly not>
It seems to meet the criteria, based on symptoms. He has what look like a calcium deposit with its shell becoming pink and red especially along the lines where the shell meets. My only hesitation at assuming this is the correct diagnosis is that the lobster has not exhibited symptoms until the last month and I have had it for two years. Could the "white spot disease" remain dormant until some environmental or nutritional deficiency caused the disease to take hold? Finally if this is the diagnosis would euthanasia be the best option so that the lobster doesn't suffer anymore? I would so appreciate a quick response. Thank-you for your time.
<The issue at hand is either a cumulative nutrient deficiency or water quality... B>
Re: FW Lobster Woes... still not reading 4/10/09

I wrote in about a week ago having problems with my blue crawfish. He has developed a red sore along one of the grooves in his back and there seems to be a nucleus to the sore. This center of the wound is white. I tried to remove it with tweezers with no success. Then, today, I noticed the white center has grown some kind of a fungus, a white cottony material is streaming from the wound, about a millimeter tall. The lobster also generally has a more reddish tinge to his shell. He is also lethargic and his appetite isn't what it should be. I read about a disease that affects invertebrates, especially prawns, but crawfish as well. I wrote in that maybe my crawfish is suffering from this disease, which ironically is called "White Spot Disease"
<White Spot Syndrome Virus (WSSV). Since this is a viral disease, there is no cure. Without access to a lab, you can't confirm the disease by sight, because unlike the situation when shrimps are infected, crayfish *do not* develop the tell-tale white spots; they just get ill and die. So for this reason, I doubt this is what your crayfish is suffering from. Much literature on WSSV available via Crayfish farming web sites and books.>
My previous inquiry was not suggesting that the lobster is suffering from the fish disease ich.
<Indeed not.>
I know the lobster doesn't have ich but he could have this other disease, no?
<There's really very little about Crayfish diseases in the hobby literature, and apart from the use of iodine supplements to improve health and moulting, there's nothing much known about treatment. It really all
comes down to optimising water quality, providing the right (vegetable-based) diet, and taking sensible preventative healthcare steps such as the use of marine aquarium iodine drops (at half-dose).>
I am looking for any information you may have.
<Sorry, can't offer very much. The best you can do is hope that following a successful moult, the damaged/infected shell will be left behind. Remove the moult to prevent re-infection, but do offer some equivalent source of calcium, e.g., an unshelled shrimp.>
Or even a link to some kind of specialist that may have more experience or information on crawfish, or on this disease that shares the same name as the legendary fish sickness.
<Google the correct name, as mentioned above.>
Is there any way to treat the crawfish?
<Not aware of any.>
Is there some other diagnosis that is possible. The lobster lives in a ten gallon tank with a couple of guppies.
Ammonia and nitrites 0ppm
Nitrates 15ppm
Ph very low @ 6.0, very acidic
<Ah! Here's one possible issue.
Crayfish (and indeed shelled animals generally) do best in hard water. While they may live in somewhat acidic habitats in the wild, under aquarium conditions problems such as pitting in the shell are common (as they are in the wild, too). Would recommend 10+ degrees dH, 5+ degrees KH, and pH 7.5-8 for Crayfish.>
Temp 66F
<May be too cold for tropical Crayfish species such as those from Australia; check the species you have an act accordingly. Cheers, Neale.>

Electric blue crayfish and a very bad molt 2/25/09 I work at my local pet store and have been allowed to take care of my own row of fish. Each row of fish has its own filter Google us if you like I work at 'That Fish Place' . We have some electric blue crayfish which I had to separate because they were slowly killing each other (2 are alone in there own tanks, the other two are in a larger tank together.). Currently the water quality is a PH of 7.6, Ammonia 0, Nitrite 0, and nitrate is 5. The nitrates were off the scale since I've got them down one of the crayfish molted and now has what looks like feathers on his side. It has been two days and he is very sluggish and still brownish pink. His tank mate molted the next day and is a very improved blue. I am not allowed to treat these tanks just keep up with everyday maintenance. Is there anything I can do for this crayfish other than adding iodine to the water. Also I read this was his gills hanging out so that means he may die doesn't it? When I ask my supervisors I'm told it was just a bad molt or blamed for it and you guys seemed like a great place to find answers. please and thank you for your help. <Hello Deanna. I'm not sure whether a Crayfish can be treated after a bad moult. The best you can do is maintain good conditions, feed it by hand if required, and hope that by its next moult things get put right. Provided it will accept food, you might be lucky. But if it isn't feeding, then the outlook is gloomy. Do have a review of these pieces, and see if you can find any clues in terms of prevention. http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm  http://www.wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm  Cheers, Neale.>

Sick crayfish 9/11/08
I have a six month old blue crayfish. He has been in perfect health up until now. I found him 2 days ago missing an eye and with a large hole in his skull where it had been. His skull itself looks odd, it has 2 pointy things sticking out of it on either side near the eye sockets. He is on his own in the tank so hasn't been fighting. Please help!!
<Hello Amy. Crayfish are prone to problems when they moult. The key issue is some sort of nutrient deficiency, probably caused by the tendency for aquarists to give them a meaty or high protein diet rather than what Crayfish should be eating: plants and algae! In theory, your Crayfish can put himself together again with successive moults, so all in not lost. But adding Iodine to the aquarium will be essential (and inexpensive). This iodine is sold as a supplement for marine aquaria, but works fine in freshwater tanks. Do read this section of Crayfish diet:
There's a link on that page to a very useful PDF at the web site of JBL. Worth keeping to hand.
Cheers, Neale.>

Help for crayfish 8/21/08 I've searched the site for additional information on this topic and haven't found anything that could help me at this point. Maybe you can help me. I have a rusty crayfish that I recently collected from the local lake. He was fine until he molted. I found him repeatedly upside down. Since then, his claws don't seem to work right. They hang under him and when he lifts them (took him two days to do this), it looks like he's punching himself in the face. He also has white feathery things hanging out from the sides since he molted. He eats the goldfish flakes and bloodworms that make it to the gravel. Is there anything I can do for him? -Nate <Nate, assuming water chemistry and water quality are good, then the thing that may be critical is diet. German aquaristic company JBL produces an excellent leaflet on crayfish you can download from their web site, here: http://www.jbl.de/factmanager/index.php?lang=en  Among other things, it makes the point that crayfish that are given too much protein in captivity moult prematurely, and this fails, causing problems. So what you've described is not at all uncommon. The key thing is that we often give crayfish the wrong food: they are HERBIVORES more than anything else. High-protein food like fish flake and bloodworms may seem nice, and they certainly eat them, but they are VERY BAD for them. Instead concentrate on plant matter, or better still, foods formulated expressly for crayfish (JBL make a couple of such products, and so likely to other manufacturers). Also remember not to feed them daily, but perhaps every other day. These animals have a low metabolism, and during winter especially may be hardly eating at all. Sabrina (another member of the WWM crew) recommends adding iodine (sold for marine tanks, e.g., Kent Marine Iodine) to the water as well. Iodine is related to the moulting process, and may be another way to help regulate moulting frequency and make sure that when it happens, it happens in the right way. She recommends a rate of one drop per ten gallons each week. Hope this helps, Neale.>
Re: Help for crayfish
8/21/08 Thank you so much! -Nate <Happy to help. Cheers, Neale>

Yabbie In Distress - 06/10/2008 Hi Crew, <Hello, Denisse. Sabrina with you today.> We have a 10-gallon aquarium, 1-Colbalt Blue Lobster <Actually, this is a crayfish/crawdad/yabbie.> & 4-Mollies. <Know, please, that the crayfish can and will eat your mollies if he can catch them.> The Lobster was doing great, until we noticed it wouldn't go into its hole anymore, had a missing antenna and was walking in circles a lot. <Excellent observations and description.> Then it wouldn't move as much, but now it seems to like being on it back for some reason. <Mm, it doesn't "like" being on its back....> It rarely moves, and the times it does move the Lobster turns back around on its legs walks about an inch or two and then turns back on its back again. <Again, *great* observation and description.> What could be wrong with it? <Almost certainly this animal is molting or has molted and is having real problems with this important process. Molting is basically where the crayfish will shed his old shell - like a snake shedding its skin - and grow. Complications with this process can cause the animal to lose limbs, form the new shell improperly, or even die. Some things that can lead to complications molting can include iodine or calcium deficiency - since most freshwater tanks have a decent amount of calcium, I would hazard a guess that he's lacking iodine. Some food items can provide iodine to him, including sushi Nori (seaweed sushi wrappers you can find in Asian food markets) and human consumption shrimp, especially the tails. If you feed him shrimp or other frozen human consumption fish or shellfish, freeze the food first or buy it frozen before feeding it to him. I like to buy the foods fresh and cut them into meal-sized pieces and then freeze them, as that makes it easier for me.> We noticed that the aquarium had some tiny white/light pink worms, some about 1/8" & others 2/8". They would crawl on the glass and gather at a corner on some larger rocks, by the "Cladoceran" apartments. <Daphnia, eh?> I always wondered how we got the worms and Cladocerans. <Tons of possibilities - foods, gravel, plants - perhaps even eggs stuck to the crayfish.> Are they harmful to fish? <Not likely. They may be a bit of an indicator that your tank is being overfed if they are very prevalent.> Are they Parasites? <Not likely.> Thank you for your time. <And thank you as well.> Denisse N Luna <Wishing you well, -Sabrina>

Crayfish parasites? Hello Crew, I have had my first crayfish, Claudine (Claude till I realized 'he' was a 'she'!) for four weeks now. She's a Cherax quadricarinatus. She shed her skin five days ago, and since then I have noticed some sort of parasite on her. I have scoured your website, but not found anything quite the same in the links. They are opaque to white in colour (and seem to get whiter as they get bigger) and look like tiny slugs. I don't think they move that much, but certainly stretch out. They have little antennae of some sort, which wave in the water. I have spotted about five of them. The most obvious sits on her head (as in the first photo), she has another couple at least in the 'cavity' around the eye area, one nearer to her 'mouth' (second photo, you can see its head near the dark patch in the middle of the picture) which is very active when she feeds, and one in the joint of one arm. I don't think they bother her, apart from the fact that she seems to 'blink' (flicks her eyes inwards!) quite a bit more than she used to. They really bother me though! I don't know whether this is normal for crustaceans as I have never kept anything like this before. The measurements for nitrites, nitrites etc. are all normal, and following the advice on your website, I have added a drop of iodide. Do you know what they are, and whether I should/can get rid of them? Are they harmful? I haven't attempted picking her up before as she's quite new and I don't want to frighten her. I think the only one I may be able to remove is the one on her head, but would need any advice on how to pick her up! Many thanks indeed for your help, Kathryn <Kathryn, it's difficult to say precisely what these little animals might be. They could be parasitic, but it's more likely they are merely commensal, that is, they live on the crayfish but don't cause any direct harm. There are a few similar reports on the Crayfish FAQ page, here: http://www.wetwebmedia.com/FWSubWebindex/crayfishfaqs.htm  In any case, treatment is likely impossible. Anything toxic to the "worms" would be poisonous to the crayfish. You could of course pull them off with tweezers or forceps, but at a risk of harming the crayfish. You could remove the next molt as soon as you see it, on the theory that might lessen the chances of re-infection (though crayfish do best when allowed to eat their molts and recycle the minerals therein). Bottom line, best left alone. Cheers, Neale.>

Crayfish died :( 5/4/08 Hey guys, I've tried searching but haven't found something that fits my situation. My crayfish died today sometime while I was out (it was mostly rust coloured/brown specs with much deeper red in its claws, about 3". sorry not sure of species). I had it for about 2 months in my 18gal aquarium with little problems i.e.: devouring 2 small angels and chasing everything it could. <Typical> even climbing my plants and freefalling to snap at the fish. I removed it to a smaller 10gal tank by itself and added a few white clouds for entertainment - they are cheap at my LFS and fast enough not to get caught. For the next 2 months almost everyone was happy (some clouds were a bit slow on the learning curve) but last week it began to get lethargic and rarely came out of its home (a small pvc length). It moulted 3 times in the first 2 months <This... is a bit too much ecdysis... telling> but never since changing tanks. <Also> I had an algae problem so over a week i cleaned all the gravel <... how?> which made it more active but as soon as the algae started coming back it stopped eating. I feed it mostly shrimp pellets occasionally a small cube of Tubifex worms goes crazy for these). the other day it looked like it was walking on its claws - pointing straight down tail in the air balancing on its claws. <Interesting...> thought it could be ammonia so i did a 20% water change. today it was upside down in the middle of the tank lifeless. Fish are all fine, reading makes me think I needed Iodine (didn't have any, apparent rookie mistake) but wouldn't it have had problems sooner not almost 5 months down the road? Sorry about the length but I enjoyed keeping my Cray and would like to again, but may opt for some shrimp instead so they can join my larger tank. thanks, Bob <Interesting to speculate, but I believe this animal was lost due to a few circumstances... One, being in a situation that was "unnaturally" warm and protein rich (allowing, driving moulting...), the strain of being moved, too much change in water quality, AND an absence of iron particles to replace its "statocyst"... an orientation organ... Please read here: statocyst of crustaceans in your search tool/s. 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.>

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>

Question on sick crayfish, reading -- 10/04/07 Hello, my daughter brought home a crayfish from school a few months ago. It was doing just fine until it had it's molting stage not to long ago. Now, It is completely lethargic. No movement unless you attempt to touch it. It has been laying on it's side for approx. 3 days now and I have no clue what to do. Can you please help?? Sincerely, Yvonne & Mykkaela <Likely something lacking nutritionally or in terms of water quality. Covered here: http://www.wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm  and the linked files above. Bob Fenner>

Crawfish death - 6/1/07 > Hello there. <Greetings.> > I am emailing with my second crawfish question; You guys really were informative concerning my first question about tank setup, etc.. Unfortunately, the crawfish in question has just expired (I think)!! <Oh dear.> > He was doing really well- we had him about a month or so, and we had his tank set up according to all of your info on your webpages. He just recently molted without any apparent problems but it seemed that he consumed almost all of his skeleton- could this have killed him? ( I read they do this). <They do indeed; it's normal, even necessary. It's a way of recycling the valuable minerals and protein.> > About 1 day after he did this, he was walking around his tank from end to end constantly, seemingly fearless, but previously, he would only come out of hiding if he sensed no one was around. Anyway, all other conditions seemed to be fine, but he is just sitting on the tank bottom, stiff, and does not move when he is touched. It sounds silly- they don't do this, right, unless they are dead? <It does sound as if he's an ex-crayfish. At the very least, he should react to being prodded. You could try shining a flashlight at him and looking to see if he reacts. Also look for signs of movement of the "limbs" around the face, particularly the small second set of antennae. There should also be movement of the swimmerets under tail. Moulting is a "sensitive" time for crayfish (and indeed crustaceans generally) and if things are going to go wrong, that's often the time. Certain minerals have to be present in the water, and conversely certain other substances, such as copper, absolutely should not be present. As a rule, most crayfish are inhabitants of clean, well oxygenated water rather than swampy conditions (though there are numerous swamp-dwelling species as well). So good water quality is important.> > Thanks so much for your insight. Diane <Good luck, 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>

Crayfish Plague -- 05/08/07 WetWeb Crew. John here. <Hello John.> I need to know about the North American Crayfish Plague. <Bad, bad voodoo. Pretty well wiped out the native crayfish species here in the UK...> I'm thinking about buying the Red Claw Crayfish, a native crayfish from Australia. The native crayfish we have here in the eastern panhandle of West Virginia is the Orconectes virilis, the Northern Crayfish. Would you guys know if my native crays carry the Plague, or if the disease is in the waters here in West Virginia. I need to know because i would like to use the water for my Red Claws. <This is a difficult question to answer. You need to get in contact with your local Fish & Wildlife agency. Assume any and all crayfish can be carriers of the Plague, and keep native species isolated from your exotic species accordingly.> Can this disease be transmitted just by using the water, or does there have to be direct contact with my native crays? The Northern Crayfish. <Virtually all non-native crayfish are banned from trade in the UK in part because they are taken by the government to be potential carriers of the plague: http://www.defra.gov.uk/fish/freshwater/crayfish.htm#PET . The Canadian fisheries web site remarks that a wide variety of European, Australian, and North American crayfish can carry the plague and/or suffer from it: http://www.pac.dfo-mpo.gc.ca/sci/shelldis/pages/cpfdcy_e.htm . So, in short, unless you can obtain categorical, scientific proof to the contrary, assume the plague can hop from native to exotic species easily. Since the plague is a fungal infection, it will be transmitted by sharing water, nets, and aquarium equipment, so you *will* need to maintain proper isolation between native crayfish and exotics.> It is very important that i have this information. Can you PLEASE HELP? <Hope this helps.> Thanks for your time. Regards John <Cheers, Neale>

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>

Cherax destructor Help - Yabby Fight - 04/04/2007 I recently bought a Yabby, a Cherax destructor I believe, <One of my favorites!> and put it in a tank with another Cherax destructor thinking they would get along just fine. <Oh, no.... Most all crayfish are aggressive, even with their own species.... The only way the two wouldn't fight is if they were prepared to mate. With the original crayfish having the whole tank as his own territory, he had the advantage....> A few nights ago the new Yabby got into a fight, it now is missing both antennas, one claw, 3 legs on the right side and 4 legs on the left side leaving a total of 3 legs... It can't walk or balance itself. <Yikes....> I have taken it out and put in into a smaller tank with a couple small Yabbies, (its claw is bigger then the biggest Yabby in the tank) <It really needs to be in a tank of its own, if it is to recover from this at all....> it now wont move at all, it just stares at you endlessly if you look at him and I have to turn him over myself when it mysteriously flips upside down because it can't turn over itself and it can't eat either. <Very, very disconcerting.... I am sorry to say that it doesn't look good for him if he's not eating.> I read the site and it says it can molt and regenerate its legs, is there anything I can do to help him molt because it doesn't seem to want to molt any time soon. <Well, though you can't force him to molt (he won't until he's ready), you can help him out a bit by making sure he's in a tank by himself and has PERFECT water quality; perhaps adding a bit of iodine (I use and recommend Kent marine iodine at a rate of one drop per 5 to 10 gallons, weekly - NOT the marine dose printed on the bottle) will help him and may even encourage him a bit to molt. Try placing VERY tempting foods (raw, frozen/thawed human-consumption fish, shrimp, etc., "stinky" foods like krill or shrimp pellets, etc.) directly in front of him to see if he might be able to eat it. If you can get him to eat, he should have a chance.> Thanks in advance. <Best of luck to you and your Cherax, -Sabrina>

Patrick-Elec blue crayfish... hlth. 3/23/07 No luck sending the email from the site. Trying again. Purchased Patrick a few weeks ago. He is in a 5 gal with five guppies. <Will eat them...> At first, he ate one every few days, moved around alot. <No such word> Now, in the last two days, he has lost both big pinchers <Something amiss here... water quality most likely, perhaps nutrition> and has not eaten a guppy in a while. Doesn't seem to move alot. <Still no such word> Seems unhappy. Is this normal? Is losing the pinchers part of molting? Should I leave them in the tank? I would hate to lose him. <Please read here: http://www.wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm and the linked files above, particularly "Systems", "Feeding"> Could it be he is crowded and breaking off his pinchers? <No> I never see him eat. Flakes and shrimp pellets just lie on the gravel. Should I try feeding him something else? Injure a guppy? <Please read...> I am working on getting him into a ten gal. with more hiding places. Thanks for your help. Melodie McClain <Knowledge is power... be powerful. Bob Fenner>

Confused about Iodine for my freshwater yabbies - 02/11/2007 Hi again. Since last emailing we've had more Yabby deaths however we have learned a lot in the process so I'm confident our remaining three yabbies are going to do ok. <Ah, good> We ended up having to put our smaller male (Homer) in with our only surviving female (Mindy) in the larger tank (14 gallons). Our larger male is VERY aggressive so now has been named Hannibal by my husband (due to his fondness of eating his tank mates) <Heeee! Give that Carthaginian some grief relief... he only used to put spears through the feet of bearers of ill messages...> and put into the 5+ gallon tank on his own. All yabbies seem rather happy with the arrangement. I've been buying bits and pieces here and there and I think I now have the maintenance sorted and both tanks look really good. <Very good> I read in your FAQs that iodine would be a beneficial additive to their water. None of the aquarium suppliers in my area sell any. <Mmm, you can easily use "human" sources for such...> Although one remembered they did stock it once but phased it out due to little or no demand. I finally found some at an Australian online aquarium supplier so have bought that. I'm not sure how to tell if it is the right stuff though (is there a wrong stuff?) so I thought I'd come here and ask. It is called Success Iodine made by Red Sea, the label reading 'Iodine replenished essential for soft corals and invertebrates'. It says nothing about ingredients other that 'contains potassium Iodide'. Its dosage recommendations for reef and marine tanks is 5 ml for each 120 liters (31 gals). So my questions are... is this the right stuff? And, if it is the right stuff, is one drop per 10 gallons, once a week, still the dosage to use in my freshwater tanks? <Is fine to use... and this dosage, interval is fine as well> Many thanks for taking the time to answer this. The differences between our countries and various companies producing these products can make this kind of thing so confusing. I've been able to find no Australian information regarding this at all. Kind regards Tascha Marshall NSW, Australia <Happy to assist you. Bob Fenner>
Re: Confused about Iodine for my freshwater yabbies. 2/12/07
I swear my yabbies know when I email you and conspire to make me eat my words. <Heeee!> I thought I had it all under control but now my females behaviour is concerning me. I'm not sure if she is injured or producing eggs or what is going on. Help??! We keep finding her on her side in cozy hiding places. A couple of times we thought she was dead only to have her move away when we've got too close. I've also noticed her tail is curled under, which I know is not usually a good sign. <Mmm...> I haven't seen her eat, but then again I can't claim to have seen her eat before this. She tends to wait until no one is about before going out and finding her food. <Most such crustaceans are predaceous on each other... the smaller ones often eaten by their larger kin...> Just now I noticed her on her side again with what looks like a blue coloured bubble coming out from the side of her tail. I didn't notice it until I tapped the glass (I'm a slow learner.. I thought she was dead again) and she moved, and the bubble disappeared under her tail. Has she mated and produced eggs (I can't find pictures online of what they ought to look like) or has she some kind of injury? <Perhaps the latter... maybe developmental> Thanks for any help you can offer me. Kind regards A totally confused Tascha Marshall Aus. <You do have sufficient alkalinity and biomineral present I hope... some very soft waters need supplementation to keep these animals. Bob Fenner>

Unidentified Yabby 'bubble' 2nd email - photos attached. 2/13/07 Hi, just me again. <Hello> I've taken some very unclear photos to show you the 'bubble'. I apologies for their quality. I can get pretty good shots of the Yabby in the other tank as it has a built in light. But with this tank one I'm at the mercy of the camera flash and I just can't get the settings right. After much research online I'm wondering now could it be a sperm sac? <Possibly> I cannot find any photos on the net so I'm hoping one of you nice people with experience in this area will be able to confirm or dismiss that theory. Thanks again. Kind regards Tascha Aus. <Same response as before... not much to do other than provide a decent environment (including chem., physical) and nutrition. BobF>

Re: Blue Lobster ill 2/2/07 Nope Pics of crayfish with growths?? on pincers <Very nice pic... This appears to be an algal growth (likely a Blue-Green... Nothing to worry about really... may likely "go" with time... molting. Cheers, Bob Fenner>

Crayfish Concerns, Medication - 01/23/2007 I've been scouring the internet and asking local fish store owners how I might treat my blue fresh water lobster. I noticed two weeks ago it wasn't eating and has some sort of growths on its large pincers and now it's developing around its mouth. Looks like fuzzy semi transparent growths. I've been changing the water on a regular basis but admit I was behind on this right before he became ill.... and I know they are very sensitive to water conditions. <What are your ammonia, nitrite, and nitrate readings on this tank? How big is the tank? How big is the crayfish? What else is living with it?> I don't have a clue how to treat something with an exoskeleton like this. <The typical rule of thumb is "don't". Currently, there is very little known about diseases and treatments of freshwater invertebrates. Adding medications to water with invertebrates is asking for trouble. Unless the animal is going to die otherwise, it's best not to play with medications and inverts.> Is it bacterial? fungal? <Without a much more detailed description and preferably an image, I do not know. I can tell you some Males of some Macrobrachium species shrimps develop fluffy growths on their claws naturally; it looks like "fur" of a sort, and may be part of attracting a mate. Algae can grow on the carapace of a crayfish or shrimp; though this is not desirable, it's usually harmless. My point here is that, since you have no idea what it is as yet, medicating is a bad idea.> I've tried PimaFix, MelaFix and it didn't seem to help. <In my opinion, these are worthless, and may even be harmful to invertebrates.> Now using Rally (Acriflavine) for two days and waiting till tomorrow to see if it is working. <This may prove fatal to your crayfish - medicating a crayfish is risky business at best. If the animal seems no worse for wear tomorrow, you might consider continuing with this, but if it were me, I wouldn't. I can't tell you for certain that it will be harmful to him, but I can also tell you were it me/my pet, I wouldn't be risking it.> Any ideas what it is and if there is a better treatment that won't kill it? <Pristine water quality, iodine supplements (if you're not using iodine, maybe now is a good time to start - I use Kent marine iodine at a VERY low dose, one drop per ten gallons every week, NOT the marine dose recommended on the bottle), and patience.... If the animal appears to be in distress from these growths, you might even try taking the critter out of the water and gently rubbing them off with a finger or wet paper towel if you are quite certain that they are not "normal" parts of him. Use extreme caution not to harm him if you try this.> Thanks for your help, -Brad Bennett <Best of luck to you with him, and please do try to get some pictures of this if you can; this may help in trying to find out what is wrong and how to fix it. Wishing you well, -Sabrina>
Crayfish Concerns, Medication - II - 01/24/2007
Thank you so much for the quick reply, very impressed with your comments and if I'm able I will get pictures. <That would be excellent. I'd love to continue to help you discover what this issue is, and how to solve it if it is in fact a problem.> Sincerely, -Brad <All the best to you, -Sabrina>

Help me please!!! Cray in the way in an African Cichlid Tank 1/3/07 Hey how is it going? <Might fine> I have an electric blue Lobster (Crayfish) and he is in my 70 gallon African Cichlid tank (he has been in there for about 6 months and the fish do not bug him (unless he strolls through their breeding area)). <Or should s/he molt...> I have had him for about 10 months and he has doubled in size. <Oh! Has molted a few times then> He has lived through Ich twice. <Mmm, crayfish don't "get" this> I have found him dried up on the floor after he crawled out one night and he still seems to be good and healthy. <Ah good> I change the water in the tank at least once a week (as the cichlids are so demanding). <Yes> All of my water parameters are good and the tank is thriving with about 2000 baby cichlids from about 5 different species of fish. <Wowzah!> My lobster (His name is Claude) <... Am given to suggest you get some "Mud-fish"... and have them next door, name them "Jean-Claude Killifish"> is still eating and roaming the tank as he normally is and all is good but I got home tonight and I noticed a black spot about the size of half a dime on each side of his body right behind his head!!!! <Mmm, possibly fungal... but most likely due to an insufficiency in biomineral and/or alkalinity...> Could you please tell me what this is and how I can fix it. <Yep... please read here: http://wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm and the linked files above. Bob Fenner> I do not want to lose him as he is the life of the tank. Please help me. Any help is good help. Thank you so much. Dustan <Welcome>

Yabbie Lobster - 09/14/06 Hey, <Neigh!> Bought a Yabbie lobster last week and set up her tank with a little bridge beside the filter which she hides under, some gravel, pebbles and a sand filled pot. She seemed happy enough until I put the sand pot in and turned the temp up slightly (from 24 to 26). Now she seems to be scratching all over and pulling at herself... she does have little white specs on her head but they could be bits of sand? <Could be sand... but there are...> Or could they be parasites? Or could she be molting? lol please help! Rob, UK <Please read here: http://www.wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm and the linked files above. Bob Fenner>

A crayfish died, owner not reading - 8/10/2006 I had a crayfish for a year. Yesterday, one of his claws fell off and today I found him dead. His shell didn't look too healthy: some white and black spots. Do you know what could have happened to him? Thank you <Likely some aspect of unsuitable or vacillating water quality... Gone over here: http://www.wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm and the linked files above. Bob Fenner>

My Electric Blue... lobster/s, Poor English 8/4/06 Hello, <Hi there> I have a 255 ltr tank, in which a have a variety of fresh water fish and live plants also had 2 marrons, <... the Crayfish?> of which 1 has died, the problem is the 2nd 1 is lying on its side all the time like the other 1 did before it died. <Water quality troubles, or overt poisoning> It's between 20cm and 25 cm long and use to be very active until 2 days ago his colour looks good and the fish don't go near him as he showed them whose boss at the beginning. Have found him on the floor, <Where are the spaces between your sentences?> after he climbed out of the tank because I had it too full. The ph level is good and temperature is fine. I know I haven't giving you much help but that's all I can give you, hope you can give me some idea as what's wrong Thanks David <Please read here: http://www.wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm and the linked files below... and learn to/use your English tools to learn/present clear communication. Bob Fenner>

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>

Freshwater Crayfish Infested with White worms. (Branchiobdellida?) - 0713/2006 Hi to whomever reads my email. <Sabrina with you, today.> My little Procambarus clarkii (Leonid) has been living by himself for a while and has been doing ok, we bought a better sponge filter for him, and took him out to examine him as a checkup. We noticed the parasites <Your guess that these are Branchiobdellida is probably spot-on. Typically, these are harmless, but there may be some species that can damage the animal somewhat.> and have a Malachite green and Chitosan formula (Mardel Maracide) which we tried using on a fish (Betta). We counted at least 10 of them that were visible. Is this Maracide safe to use on a crayfish? <No. This is toxic (at best) to the Cray, and may even kill it. In general, it is best to just never use medications with invertebrates present. Most anything designed to kill parasites will harm pet invertebrates. If you feel you must remove these worms, do so manually by gently (gently!) scraping them off with a fingernail, cloth, or brush with the Cray submerged in a bowl of tank water.> Also, is there any possible way to prevent this from recurring? <Not effectively. Just remove as you see necessary.> One other question not related to the Worms, my other 2 crayfish are robustus, <Neat!> and one is female, the other male. If I choose to breed them, how much of a size difference between them can there be? <Preferably not significant, or the larger animal may damage the smaller one.> The male (Vladimir) is about an inch longer than the female (Mavra). <Mm, not quite descriptive enough.... I mean, if the male is 2" and the female is 1", this is a significant difference.... though, at that size, they're not going to breed :grin: If, on the other hand, the male's 7" and the female's 6", this is a fine size, and no worries.> All help appreciated, Colin. <All the best to you and your crayfish! -Sabrina>
Freshwater Crayfish Infested with White worms. (Branchiobdellida?) - II - 071*/2006
A more descriptive way to explain would be that measuring from tip of the head to tail, Vladimir is about 4 1/2 inches and Mavra is about 3 inches. I am thinking of waiting a while for Mavra to molt and I think this will allow her to get within a 3/4 of an inch of Vladimir, hoping she could possibly become 3 1/2 to 4 inches. <Sounds good. I might give it a little longer. Definitely wait until her shell's hardened completely - a few to several days after moulting, if possible.> They share a tank with a divider in the middle, and I see them looking at each other. Do you think this could be considered flirting? <Either it's crayfish love, or they're looking at each other as a potential dinner. I'd bet they're starting to feel amorous.> Also with the Cray and the meds, we had tried the meds before I received your most informative response, <Yikes!> he sat in the formula for a couple of hours and when I saw the email I quickly picked him out and changed the water. <Ahh, whew! I'm VERY glad to hear/read this. Thank you for acting quickly. All the best to you, -Sabrina>

Re: Freshwater Crayfish Infested with White worms. (Branchiobdellida?) Crayfish Continued - 07/27/2006
Dear Sabrina, <Hi, Colin!> I am very happy that I can email you using my Gmail's reply, you are the most valuable source of information about my freshwater crayfish. <Glad to be of service.> My dwarf frogs have died off, <.... why?> but left a nice open area for someone to live, I am considering getting a new 10 gal tank and giving it to Mavra, then Vladimir, being the bigger Cray, shall get the whole 15 gallons to himself. Would it be a good idea to introduce Vladimir to Mavra when we decide to, inside of the 10 gal, then allow Mavra to go through her short period of motherhood before moving her to somewhere else? <Possibly. Just be sure that there are LOTS of good nooks and crannies for her to hide in. A pile of PVC joints and elbows or clusters of rocks/caves would be good.> My father thinks some kind of Cleaner shrimp would help the tanks, but I am afraid the crayfish would just eat them, <Likely - but possibly they'd be ignored. I'd make an attempt with very inexpensive shrimp (like ghost/grass shrimp) if you try this.> if shrimp would not work, what else would be safe from the power of the Cray? <Maaaaaaybe snails.... Perhaps Septaria sp. snails would work best....> Big news with Mavra, her rear left leg is growing back. <Excellent!!> We noticed a small white pinkie growing out of her leg, and now it is growing larger. <This is a very clear sign of good health.> I appreciate all of your help and wisdom, Colin <As always, I'm glad to help out. Wishing you well, -Sabrina>

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>

Crayfish, Claws, and Complications - 04/20/2006 Hello. <Hi.> I am hoping this is the email I send my FAQ's to. <It is.> If not, please help me figure out where I do ask the questions. :-D <Right here, matey.> Anyways...I have a red freshwater crayfish. <Probably Procambarus clarkii, if you're in the US. These are common at pet shops, and make awesome pets.> He is in a 55 gallon tank with: 7 guppies, 2 five inch long feeder fish, and 3 hatchet fish. <Do please be aware that any of these fish *might* become midnight snacks - but hopefully are "fast" enough not to get snatched up.> I was reading through the other FAQ's to find some info on crayfish not molting. When I got my crayfish, he molted instantly. In the process of molting, he pulled off his own claw. <Ouch!> His claw then began to grow back again. Then he/she molted again and pulled the newly grown claw off AGAIN. <Disconcerting....> Now he hasn't molted for a couple months, and its claw is not growing back. <VERY disconcerting....> You requested others with the same problem to add iodine to the water. <Yes. Urgent.> Would that affect my other fish that are in the tank? <Nope. Just use the rule of thumb I usually recommend - one drop of Kent marine iodine per ten gallons weekly. Note that this is NOT the marine dose printed on the bottle. In this fellow's case, for the first couple/few weeks that you do this, I'd use two drops per ten gallons, then in a few weeks, go to one drop per ten. This won't affect your fish.> I also don't really feed the crayfish. <A problem.... especially since if he's hungry, those guppies are going to start looking very tasty to him....> He just eats the extra fish food that floats to the bottom. <That's good. Also offer him bits of frozen (then thawed) raw human-consumption shrimp, preferably the tails.> I tried feeding him uncooked bacon strips, but the guppies would eat it and keep the crayfish away. <Don't offer any land mammal or poultry meats - not only are these bad for the Cray, but bad for the fish, too.> Could a bad eating diet be keeping him from growing his claw too? <Yes.> He sometimes eats the fish that die, but my fish don't die too frequently. <Probably only once, I imagine! Dead fish are pretty much "okay" for him to eat, just not so okay to leave in the tank.> If I should be feeding the crayfish something healthier than left over fish food, what do you recommend? <As above, shrimp is good, also frozen/thawed human consumption fish meats, or sinking meaty foods. You can give him these things just after you turn the lights out so he'll have a better chance at finding it than the fish.> How would I keep my other fish from eating the food that is meant for the crayfish? <Whups, I jumped the gun. Feed him just after lights-out on the tank.> Oh yeah, just something to add in real quick. My fish had ick recently, so I added "Kordon Rid Ich+." Is it unhealthy for my crayfish to be in the tank when I am treating the fish for ick? <Yes, VERY.> The crayfish is still alive, and the crayfish has been in the tank every time I have treated the fish for ick, so I cant imagine it being TOO harmful for the crayfish. <It is *very* harmful for him, and may be part of the reason he's not moulting well for you. Please, please read on WWM regarding quarantine tanks - please quarantine any new livestock for two weeks minimum *before* adding them to your tank; this will keep your other fish safe from ich and you should not have to ever treat ich in your main tank again.> Have a nice day <You as well, thanks.> *A crayfish owner needing help. <-Sabrina>

Crayfish Starting from scratch here. We have success in sustaining crayfish. We have had zero success in growing the tank population. What could we be doing wrong? <Likely the ones there already are eating each other. Especially when they molt (shed their external skeleton, to grow) crayfish are very susceptible to predation. Maybe adding more rockwork, some plants (plastic or real) will help boost your population. If you're expecting them to reproduce, there are a number of reasons why their young may not be being produced or likely being consumed as well. Bob Fenner>

Crayfish Hi Bob Fenner I have a 2.5gallon tank with a crayfish and a 29gallon hard alkaline cichlid tank with a divider. I want to move the crayfish to the empty portion of the 29gallon tank and was wondering how to go about acclimating him from his neutral water. <I would "drip acclimate" the crayfish/crawdad to the new water by placing it in a lower position, dropping half the water out, and use a length of airline tubing (with an adjustable knot) to drip (about one drop a second) the cichlid water into its smaller system... Most species (yours... likely an astacid... maybe Procambarus clarkii?) will make this transition easily... after this abrupt mixing, just place the animal by scooping it into a bag or plastic container underwater and put in the larger system> Ps. I appreciate your past help, and the speed at which you have replied. <You proverbially "ain't seen nothing yet". Bob Fenner>

Cherax quadricarinatus - Red Claw Crayfish/"Lobster", Molting Issues Hi I have a red claw lobster and it is laying on its side and it is still moving and it looks like it is molting because some of the shell is off. I was wondering if it is molting or is it dying. <Tough to say, I'm afraid. Laying on his side is not a good sign, I must say. It does sound like he's having difficulties with molting, a "bad molt", as it were. At this point, the best you can do is wait and see. In the future, though, please consider adding iodine to his tank, to help him with his molts in the future. I use Kent Marine iodine (marketed for saltwater tanks) at a rate of one drop per ten gallons every week. The difference this tiny bit of iodine makes is truly amazing. Since using iodine in my freshwater shrimp tanks, I haven't lost a shrimp to a "bad molt". For now, just leave him in peace, and hope he recovers. If he does, do please start dosing iodine in his tank to prevent this from happening again; if he doesn't, well, at least you know you can prevent it from happening to future pet crayfish. My fingers are crossed for your crustacean pal.> Can you e-mail me back at XXXX please. <Done. Wishing you well, -Sabrina>
Cherax quadricarinatus - Red Claw Crayfish/"Lobster", Molting Issues, II (01/31/2004)
I am sorry for e-mailing you back here it's just I don't know what XXXX means. <Since we post these questions and answers for all our readers to read, and you had posted your email in the text of the message, I removed it; that's all the X's were for. While on this note, though, the text sent back with this reply was very, very jumbled; I hope that it made it through to you okay.> My lobster has been laying on it's side for 3 days and only a little bit of it's shell is off. It looks like he is trying really hard to get the rest of the shell off. What should I do? <If there are any other animals in the tank with him, it'd be a good idea to quarantine him separately to help him recover. Then I would certainly add iodine (I use Kent marine iodine at a rate of one drop per ten gallons) to his tank; this might help him out. Further, you should definitely check your water parameters (ammonia, nitrite, nitrate, and pH), and ensure that ammonia and nitrite are zero, and that nitrate is as low as possible. If not, do water changes to correct the issue. Any of these values being too seriously out of whack could cause harm to your crayfish. Wishing you well, -Sabrina>

Blue Crayfish Dear Crew, especially Sabrina, <Sorry, I stole the email from Sabrina, Gage here, your local Crawdaddy fanatic.> I have a little blue crayfish, nearly 3" long, 2 years old, called Lopez. At the last molt (Sunday) he got a leg stuck and when he finally got it out, the leg/pincer was at an odd angle, kind of backwards, clumsy looking. He is moving and eating (lots) and can still use the leg and pincer, but it is certainly not right. It is bent backwards and gets in his way when he tries to hide in his jar/burrow, though he gets in in the end. I am wondering whether to somehow tweak it off (ouch) so he can grow a new one. But really, I am scared to hurt him and would rather think he will be fine and that he is not in pain as he is. What do you think? How can I tell? And if you think I really must tweak it off, any advice on how to do so...?? I really like this little fellow and want to do my best for him. Any help appreciated. <I vote to leave it, I do not think it is worth the stress of breaking it off. Chances are he will correct it himself in the next few molts. Best Regards, Gage> Cheers, Andy
Blue Crayfish, cont'd
Many thanks for the swift reply. I am inclining towards leaving it. <I definitely agree with Gage here, better to leave it.> If he was in pain, I think I'd see differences in his behavior wouldn't I? <I would think so, yes. If he's eating, acting normal, let 'I'm be.> He looks to be acting as usual, but with a dicky leg... Andy <I would strongly recommend adding iodine to his tank if you don't already, and if you do, to increase the amount by just a bit until his next molt. I use Kent marine iodine, at a rate of one drop per ten gallons every week. Wishing your lame pal a swift recovery, -Sabrina>

- Crayfish Parasites - I have two freshwater crayfish (they are probably Florida Crayfish and they are approximately 3" long) in an Eclipse Six Tank. We have had them a few months. I just noticed many parasites on them. They look like small white worms approximately 1/16 - 1/8" long. <Quite likely one or more varieties of Branchiobdella which is an obligate crayfish parasite.> I also see white specs all over the glass. How do I kill these parasites without killing the crayfish? <Hmm... well, I had to look this up on the Internet and actually used Google and put in the subject of your email, "Crayfish Parasite" - if this is indeed Branchiobdella then there is no known treatment. Do not introduce these crayfish into the wild or to other captive crayfish as the parasite will spread.> Please advise A.S.A.P. Thank you. <Cheers, J -- >

Crayfish Kicking the Bucket? >Hi, >>Hello. >I have a blue freshwater crayfish, and I think he might be dying - he's been on his back for about a day and he doesn't move around much. >>Not sounding too good. >Every once and awhile he moves his legs, but some of them are at a funny angles. >>Sounds as though you're describing a roach sprayed with Raid. >He previously lost a claw, and I am wondering if he's trying to molt and is having trouble with the regeneration of his claw, or is maybe stuck or something. >>Difficult to tell. For the most part, I've found mudpuppies both easy to care for and mighty good eating (born in New Orleans, hope you can understand the sentiment). They lose claws all the time, and in shipping we tend to find better behavior within the group of we go ahead and pinch the claws of those with larger appendages. >I talked to the fish department at a pet store, and they said that sometimes a molt goes badly and the animal grows back into the old shell. >>Um.. I've not quite heard this sort of explanation, "Grows back into the old shell". A molt can go badly, but it's a bit uncommon, especially with animals as (relatively) hardy as crawdads. >Could this be happening, and if not, what is? >>This is very difficult to tell. I would first wonder if you had VERY soft water with little mineral content. Unfortunately, even if you do, it may not be of any help to buffer it at this point. >Is he dying? >>It doesn't sound as though he's in very good shape at all, I'm sorry to say. You haven't mentioned any water testing or parameters, and this could be an issue. I suggest testing for the usual suspects, and doing a water change anyway, trying not to disturb him. >Is there any way I can help him? >>As above. >Any advice will be well appreciated - I love this animal! Thanks! Robin >>Beyond what I've mentioned above, I can't offer much more in the way of help for your pet. If it's a very large individual, he could just be old. In any event, I would still test the water and do a change or two, just in case. Marina

Freshwater "Lobster" Troubles Hello, <Hi Lace, Sabrina here today> My Daughter has a 10 gallon aquarium, in it she has a blue lobster. <Just to clarify, in case you're interested, this is probably either one of the blue crayfishes available in the hobby, or perhaps one of the two Macrobrachium shrimp species available that are blue.> It appears it has now gotten a thread like thing on it. She thinks it could be worms. It's condition has gotten worse and I would like to know what to do to get rid of what it has. <I'm afraid this is kind of vague.... Could you please describe this in more detail? Are there many of these thread-like things? Where are they located on the animal? How are they attached? Does it look like it's part of the shell (perhaps coloration), or are they sticking out? If there is any way you could email us a picture of the animal and its condition, this would help tremendously.> Could you please give me some advise on how to help it, I've grown quite fond of it and would like to help get rid of these things, what ever they may be. <To try to figure out what these thread-like things are, I really do need some more information, as above. It would also help to know what else (if anything) is living in the tank with it, how long you've had it, how large it is, and what the water parameters in the tank are (Ph, ammonia, nitrite, nitrate). If you don't have test kits to find out your water parameters, you can take a sample of your water to the fish store, they should be willing to test it for you. I'd also like to mention here, it is very beneficial to add aquarium iodine to tanks with freshwater invertebrates; I use Kent Iodine, marketed for saltwater aquariums. Only one drop of Kent Iodine for every ten gallons once a week really vastly improves invertebrate health. I have seen this in my own shrimps and even the few large snails that have escaped removal. Just a side thought. Please get back to us, Lace, and let us know a bit more details on your pet's condition, and we'll do our best to help you out. -Sabrina> Thanks for your help. Sincerely, Lace

Crayfish parasites I have an electric blue crayfish which I purchased a couple of weeks ago at our local pet store. Over the past couple of days I have noticed some (5) small white creatures (approximately 1/8th inch) that are inhabiting around the nose and the base of the feelers. They look like a tube with 2 tiny arms at the top (one on each side) and as I was watching them one of them kind of flipped end over end to move up the crayfish's head. Also when I was feeding my other fish in the tank (33 Gal) and the flake food moved past one of these so called parasites it looked like it tried to grab it. Any ideas as to what these are or do you require further information. <I'm sorry I really am uneducated in crayfish other than catching them in the local creeks here, so I had to look up and see what I could find. You might look at this site which seems to really have a handle on crayfish http://us.geocities.com/crayfishdisease/pages/intro.html. Good luck, MacL> Thanks, James

Crayfish With Ich? - 12/13/2004 Hi, I was wondering if crayfish can get ich. <No. Ich (Ichthyophthirius multifilius) is an obligate fish parasite - the Cray cannot be affected by ich. A Cray can, however, have ich cysts stuck to it, while the cysts are reproducing and before they become free-swimming in search of fish. These would be totally invisible to the naked eye, and can be stuck to anything from an infected tank - gravel, plant, and crayfish alike.> I have one that I saved from the feeder goldfish tank at my work. Once I got it home I realized it has what looks like ich on it. <It's more likely either his coloring or bits of detritus stuck to him. I wouldn't be terribly worried.> I can't seem to find any info on treating crayfish with ich though, which made me wonder if it is ich at all. <Very, very highly unlikely.> I do not want to introduce him to my tank if he could make all my fish sick. <As above, he can have (invisible) cysts stuck to him - I wouldn't be too worried, but it would be best to quarantine him anyway, as it is best to do before introducing any animal to your established tank.> I have a 20 gallon heavily planted (swords, and frills) tank with one Creamsicle and one silver Lyre-tail (sp?) molly, their new fry, a dragon fish, <This common name is applied to a few different critters.... but any one of them (Polypterus sp., Erpetoichthys sp., Gobioides sp.) will all outgrow a 20g tank in short order - and the last, Gobioides, is a brackish animal. Please research this fellah a bit, find out what you have, and what your options for it might be.> a rummy nose tetra, and a gold mystery snail. I really don't want to get ich and have to uproot my whole tank. <Agreed. Ich sucks.> Any info would be great. <As above, your absolute safest bet is to quarantine *any* new livestock before adding to your tank. BUT - this is pretty important - a crayfish really isn't a good tankmate for any of the fish that you've mentioned; any/all of them are more than likely to end up as crayfish food eventually. I urge you to set up a new tank for the Cray (even just a very, very simple 10-gallon setup would suffice). One cool bonus is that this is more than likely Procambarus clarkii, and you would not at all need a heater for his tank. Crayfish are unbelievably interesting animals to watch and care for, I think you would really appreciate him if you can give him a place to call home. I also urge you to read crewmember Gage Hartford's excellent and fun article in our online Conscientious Aquarist e-zine, on care and breeding of crayfish: http://www.wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm > Thanks, Candice <Wishing you and your crayfish well, -Sabrina>

Yabberin' about a Yabby Hi there We have a pet Yabby, named Minnie, and she has recently lost her shell and is looking great except for these black spots that appear to be spreading. The tank is always clean and we have had her for about 12 months and this is the first time she has had black spots. We have recently moved house and her tank now lives indoors with no natural light whereas previously she lived in a tank outside under shelter with exposure to natural light. Perhaps this has something to do with it??? Cheers Amy and Corey <Maybe... could be nothing, could be mineral content of your water, nutritional, perhaps an iodine/ide deficiency... Please read here: http://www.wetwebmedia.com/FWSubWebIndex/fwcrustaceans.htm the Related FAQs files above. Bob Fenner>

Non-molting FW Crayfish I have had a blue crayfish for about 8 months. He seemed to be doing well, and, at first, he molted every four weeks about three times. He has not molted for about three months. <Mmm, perhaps a nutritional or iodine, other deficiency is slowing down its rate of growth/molting?> He is about four inches long. He lives in a ten gallon tank with no other creatures. I feed him algae wafers. He does not seem to like anything else. <Unusual> I give him shrimp pellets, and I recently tried frozen krill, without success. For the past two weeks, he seems like he can't see and as if he is about to molt. The problem is he has not molted and does not appear to be interested in eating. <Am wondering re this system water quality... do you test for pH, alkalinity? Do you supplement iodine/ide?> He would normally grab the algae wafers and come over to the tank when he saw us. Now he seems to walk around and remain still in one spot for hours, but does not respond to our presence. His water is clean. I monitor it for ammonia. His temperature varies with room temperature from 68 to 75 degrees. I don't know what to do for him, and I don't know what is going on with him. Please e-mail me at XXXX with any ideas at your earliest convenience. The pet shop told me to put a drop of Kent Marine Iodine in his water to help him molt. <Ahh, a good idea> I did this three days ago. Our water is alkaline naturally. Thanks, Louise <I encourage you to put the terms: "blue crayfish keeping" in your search tools and read a bit further re this animal's practical husbandry. It needs other food... Bob Fenner>

CRAYFISH AMPUTEE Thank you for the quick response...one other question...In this same tank I have a blue crayfish...apparently, one of my Bala sharks got a hold of him right after he molted and ripped one of his big pincher arms off...all of it is gone. Will it grow back? < Yes but it may not be the same and take a few molts to get back to its original size.-Chuck>

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 Safe Ich Medication Hello crew (probably Sabrina), <Sorry, Ya got Don tonight. Sabrina's birthday today. Hope she has a happy one> I apologize for resorting to e-mailing you, but I've searched quite a bit and I can't seem to find what I'm looking for. Neptune, my electric blue crayfish (Procambarus alleni), lives in a 55 gallon tank with a small selection of plants, 2 gold Gouramis, 2 blue Gouramis, a large Plecostomus (Jacques), a dinosaur eel (Scuttlebutt), a baby whale fish, and a temporarily small Arowana. I made the hasty mistake of dumping in some small feeder guppies for the Arowana without quarantining them. Now I have a fun little (deserved) ich outbreak. I've slowly elevated the temperature to the mid-80's (Fahrenheit) and added some salt. The ich doesn't seem to be giving in that easily though, so I am going to medicate my tank. I currently have Quick cure. I understand that copper is quite unhealthy for my crayfish. The Quick cure label only lists the active ingredients (formalin and malachite green). Is Quick cure safe to use with my crayfish? If not, is there another effective medication that is crayfish-safe? Would it be best to just remove my crayfish into my empty QT and medicate the main tank? If it is, I read that the too-small-to-see ich cysts can stick to a crayfish, so would my tank be re-infested when I moved the crayfish back? Again, I apologize for bothering you, but at least now anyone else with these questions will be able to find them! Thanks in advance for your help (again). -AJ in Florida <Don't use the copper in any tank where you may someday keep inverts. Months, and dozens of water changes, later it can still kill. If your QT is large enough to house all your fish for four to six weeks, move all the fish (but not the crayfish) and treat them in QT. Leaving the 55 fishless while treating in QT will starve out the parasites. If not then you will have to move the crayfish into the QT and treat the main. Treating in the main is a last resort as the meds will nuke your bio filtration resulting in ammonia spikes. This will require that you do many large water changes to keep your fish alive, replacing the med with each. Much easier (and cheaper) in a small QT. I would use heat and salt only, no matter where you treat. Your eel and Plec will be badly stressed by copper. Possibly to the point of killing them. Salt is much easier on the fish and 100% effective if used at the proper dosage, 76 grams per 10 gallons. For a 55 gallon that works out to 418 grams or just under 15 ounces. Make a brine out of tank water and add it back over a day or two. Take the temp up to 84. When ever you do a water change add the same concentration of salt to the new water before adding it to the tank. Of course you will need to test for ammonia and nitrite during any treatment. Continue treatment for at least two weeks after the last spot drops. Always use a gravel vac to remove water. The Ich reproduces at the bottom of your tank. You have a lot of work ahead of you. Get your fish off of feeders. And oh yeah, the crayfish. Just keep him away from any fish for the four to six weeks and any hitch hikers will starve out. He can not be infected. Good luck. Don>

Lost my Lobster, Losing my Fish Hello there my name is Cody, I have a couple questions, fist off, I just lost my blue cobalt lobster. We had him for about 6-7 months. My questions are, do you think that when he died if he could have gave the tank some kind of disease? <Possibly, but doubtful. Most FW crustaceans die from poor water quality issues, most of the remainder from a lack of nutrition> For some reason a few days before he passed away all of our fish looked and acted fine. Now that he died, just this past couple of days we have lost 3 fish. One of them, what looked like it was bleeding from the bottom of his fins, the others had red spots. Please help we are afraid that we are going to loose our other fish. Thanks a lot. Cody <Time to check your water quality, do water changes... Bob Fenner>

Crayfish Worms 6.12.05 I bought a small blue crayfish from a local pet store. After he molted for the first time I noticed some white worm like parasites on the top of his head. These worms multiplied all over his body seeming to be located around joints and the bottom of his tail. These worms also seem to be getting longer as the days go by. Watching the worms closely I noticed that they seem to be trying to pick up food. I am very worried and can't seem to find any sites to help. Hope to hear from you soon... <Ew. I have not heard of white worms that hang out on Crayfish. Are they in other areas of the tank to or just on the Crayfish? It would really help if you could send us a picture. Gage>

Electric blue crayfish worms??? I have trying the product Maracide now for the past seven days and the worms are still on my electric blue lobster (crayfish). <Yes... this product is for infectious disease agents...> I have tried to take some pictures to show you <Very nice> but as I said before the worms are so small you can't really see them. He has a small white marking on the top of his head and near the bottom of his tail were the worms stick out of. He also has about a hundred or so on the bottom of his belly. The worms are not on anything else in the tank. I also have a blue crayfish in with him and about 25 or so guppies. None of which are infected. I am sending a few pictures and hopefully you will be able to see what I'm talking about. The worms in the picture are located in the middle of his eyes. Hoping to hear from you soon Thanks <Mmm, you can/could try actual Anthelminthics, compounds that are toxic to worms, but not (much) to other invertebrates. Please see here: http://www.wetwebmedia.com/fshwrmdisfaqs.htm and the next Related FAQ file, and the links where they lead you. Bob Fenner>

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/Yabby Deaths - 08/17/2005 We purchased a Yabby last week and put it in our small(ish) tank. We had been keeping danios so we were used to changing water and keeping clean etc. The water had been treated and left for 42 hours to get rid of chemicals - all seemed well. The Yabby looked well for 3 days then it became very quiet, I partially changed water, it didn't recover and died. <Any chance you have EVER used a copper-based medication in this tank? Any metal objects in the tank?> We bought another Yabby (we had liked "Godzilla" for the short time we new him). This time, just to be sure, we used our bigger tank, conditioned the water, washed the gravel and installed a filter. A day later (today) the Yabby shows the definite signs of soon demise -it's falling on it's back or side and doesn't move (except a little when I think it's dead and I go to remove it). WHAT are we doing wrong! <Not sure. I trust you are maintaining ammonia, nitrite at zero, nitrate less than 20ppm? pH somewhere between 6.8 and 8.5?> And why does it happen so quickly. My kids are scared off from getting anymore yabbies but they were so delighted with them and they paid for them themselves. Iodine is mentioned quite a bit on your site but usually in conjunction with molting problems. Neither of the yabbies showed signs of molting. <Mm, all the same, I think a lack of iodine may indeed be a problem, here.... If you do try another Yabby, please do considering adding iodine for a week or so prior to purchase.... You've seen the FAQs, so I assume you know I use and recommend Kent marine iodine at a rate of one drop per ten gallons each week (NOT the marine dose)? I have, occasionally, doubled this when adding new shrimp from somewhat disreputable stores.... My only other thought is that there may be something in the tank(s) that is actually toxic to the crays.... Copper is the very first thing to come to mind. Medications like CopperSafe, Cupramine, Aquari-sol, all contain copper. Something to think about.> Please help, Kelly (mother and grief councilor!) <Wishing your sad patients a swift recovery, -Sabrina>

Crayfish/Yabby Deaths - 08/17/2005 Thanks for speedy reply. <Of course.> "Spartacus" died overnight (should have picked a longer-living namesake perhaps?) <Perhaps "Lazarus" next time, eh?> No copper, no medications -this tank was started from scratch with all new components and all prepared 24 hours in advance. The little fishes are still happy, water quality looks clear but i haven't the means to check chemical make-up (we were assured that these Aussie yabbies were cyclone proof, more like - don't breath too heavily!) <This reminds me of the importance of teaching folks how to distinguish healthy shrimps and crays from sick ones prior to purchase.... Can be tough, unless you know what to look for. Next time, find a Cray that is active, brightly colored and has a quality of "clarity" in the coloring.... very tough to describe, until you've seen the "opaque" look of a sick shrimp. Make sure the animal is interested in food prior to purchase, as well - if the shop employee puts in food and the Cray is not happily bumbling about looking for it, pass on that animal and look for a healthier one.> I'll try iodine if we have the nerve to try again. <Do please try again - I fear that the animal may have been quite ill prior to purchase, to die so quickly.> Thanks again for your help, -Kelly <Wishing you and your kiddos well, -Sabrina>

Yabbie Thanks - 10/20/2005 Thank you very much for the quick response of my letter. The information you gave me is very useful. Thank you again! From Jarrad <I'm glad I could be of service, Jarrad. Wishing you well, -Sabrina>

Crayfish With Worms? Parasite, or Symbiont? - 12/06/2005 Hi, <Hello.> I am a Veterinarian with very limited, if any, experience with marine animals. <Good thing crays are freshwater, then! <grin> > << <giggle> >> My son's 7th grade class has an aquarium with crayfish and he tells me that they have white worms on them, about 1/2" long. My question is, if he acquires a worm for me and I can determine whether it is a worm or a fluke, what would be the meds that I could use? Please include dosages and exactly how to administer the meds. I do have liquid Fenbendazole but it is thick and white, is this OK to use in water? Please help, if possible. <The real question here is whether these worms are actually a problem.... or whether they may be a *benefit* to the class Cray. It sounds like these are Branchiobdellids, which are often found on crayfish, and pose no threat to the animals. Though perhaps a little unsightly, these guys do seem to offer some benefit to the Cray, and apparently even consume damaged eggs of carrying females while not harming healthy eggs. Were it me/my class, I'd probably leave the worms be, and maybe make a sort of a project out of it to count the crayfish's "helpers" every now and then, and have a chance to learn about symbiosis. Here is a link with a bit of information: Worms & Crayfish .... Also, I recommend doing a Google search on "Branchiobdellid annelids"; using this term in Google Scholar might be a good idea, too. http://scholar.google.com/ . And.... to offer just a little extra (less satisfying) information.... There's just not a whole lot known or done regarding invertebrate pathology in pet inverts. The only real information in this area is in relation to the food industry, and culturing shrimp for food. The solution to pathogenic problems in the food shrimp industry is to destroy the affected stock, sterilize the affected system, and start from scratch. Of course, that won't help hobbyists, or hobbyist shrimp , and it certainly won't help a classful of 7 year olds with a beloved pet crawdaddie. This is a pet peeve of mine, and something that I hope will be remedied in the future.... One of my dreams is to go back to school for fish pathology, and try to forge a bit of a path for myself in invertebrate pathology.... but I have a hundred other dreams I desperately wish to pursue, so we'll see what happens.> Thanks, -Robin Rosen-Sharp DVM <All the best to you, your son, his class, and their Cray, -Sabrina>

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