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Crayfish, Crawdads, Yabbies, Ditch Bugs Disease Diagnosis 

FAQs on Crayfish Disease: Crayfish Disease 1, Crayfish Health 2, Crayfish Health 3, Crayfish Health 4, Crayfish Health 5, Crayfish Health ,
FAQs on Crayfish Disease by Category: Environmental, Nutritional, Trauma, Infectious, Parasitic, Social,
Treatments

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,

CHECK your water quality.... DO a water change....

Crayfish translucent growths        10/7/17
Good day!
<Bonjour!>
I impulse bought a 3" Tangerine crayfish and now I'm scrambling to buy the materials to cycle a 10g long tank but for now I'm keeping her in a small 2.5 gallon tub with a sponge filter until then. She recently molted (But lost some limbs because she had horrible shell rot from the shop) and now its been 13 days i have noticed growths from the stumps of her lost appendages!
<Indeed. These are likely 'benign' Protozoans, bacteria or fungi that grow wherever there's plenty of dead organic material. They're benign in the sense that they're not aggressive pathogens that will make your crayfish sick, but they're still undesirable. An antibacterial and antifungal medication known to be shrimp-safe (such as eSHa 2000) could be used here, alongside optimising environmental conditions. To a great degree this sort of 'fluff' grows on crayfish in tanks that have less than perfect cleanliness. The more gunk for them to feed on, the more the Protozoans and fungus will spread onto your crayfish.>
i don't have a test kit yet so i cant tell the parameters but i do a lot of partial water changes every other day and feed her veggies and sinking pellets.
<Good.>
She's acting so differently now and she's just scared of everything unlike before (maybe its because she also lost her claws).. but i digress, the growths look feathery and have spots in them, attached here is a photo i took of her in an ice cream container while i was cleaning the sand in her tub (there was rotting broccoli pieces hidden so it was stinking to high heaven)
<The photo isn't sharp enough to see exactly what the problem here, but for now, I'd assume the benign fluff described above rather than an aggressive crayfish parasite. Still, if you can get tack-sharp photos, sites like
PetShrimp.com have active forums with numerous experienced crustacean-keepers.>
Thank you for helping, I've added some antifungal meds (no copper) but i just want to help her get better soon.
<Understood. Good luck, Neale.>

Re: Crayfish translucent growths      10/8/2017
Thank you for the reply!!
<Welcome.>
Just adding again but here's another pic of Megatron i took the same day, is this photo better?
<Not really. It's not so much the size of the photo as the fact the bit of interest, the fluff around the legs, is basically a blurry mess with black speckles.>
its got dark spots and it worries me to no end.
<They look like baby crayfish, what with the black spots and all! Cheers, Neale.>

Crayfish, bad molt, and mycobacterium      12/14/16
Hello WWC,
<Close enough>
This is very long because I want to give as much information as possible. I am a college student working on my B.S. in zoology,
<Oh! My undergrad. degree as well>
so this is exactly the kind of thing that interests me and therefore I have collected a lot of information about the circumstances.
<Okay>
I have a 10 gallon freshwater aquarium with the following water conditions... the first test is from 5 days ago, and the second is after I did a water change:
First:
Nitrate <20 ppm
Nitrite 0
GH 200
KH 180
PH 7.8
Temp 64 F
Now the numbers are:
Nitrate <20 ppm
Nitrite 0
GH 150
KH 120
PH 7.6
Temp 64 F
<A bit "older"... still; acceptable values>
In the tank resides one female crayfish of unknown species and two "mosquito fish" (Gambusia affinis). I have had the crayfish since November 2, 2015 when I accidentally caught her from a pond at my school (I was netting some mosquito fish from the pond to put in an aquarium because I'm just weird like that). She was only approximately an inch long at the time, and almost translucent, with tiny little baby pincers. While reading up on crayfish, I found a recipe for a gel-type food that I could adjust to meet her needs. It uses gelatin as a binder, and is frozen after it sets, so I can break off cubes to thaw as needed. I made it with dried Spirulina, dried organic kelp, fresh spinach, fresh zucchini, cooked whole shrimp, and some salmon. It is mostly greens, though, as that seemed most appropriate.
Her diet consists of the gel food, shrimp pellets, algae pellets, fresh greens/cucumber/etc., duckweed, and sometimes frozen brine shrimp. I try to keep it varied.
<Good... I'd add a modicum of iodide-ate to the water weekly as well. Have you read on WWM Re Cray nutrition?>
Now she is approximately 4.5" long, and has molted 10 times since I brought her home. The problem started with the last molt, which was July 15, and continued with one that happened 5 days ago. Before I get to that, however, I want to express my reason for emailing you when you have so many posts already regarding bad molts.
<Ah yes>
I had some mosquito fish fry in my 5.5 gallon aquarium, and on June 5th I noticed one fry had a bent spine. I thought maybe he had been injured or something, and never considered that it could be something contagious. Then there were some other anomalies with the fish in that tank and with the tank conditions, the specifics of which probably don't matter in this context. But at some point I realized there were more than one fry with a bent spine, and finally researched it as a symptom of a larger illness, rather than an injury. I began to come to the horrible hypothesis that my tank somehow had been infected with mycobacterium. It explained many of the abnormalities I had encountered.
<Mmm; well.... This genus of bacteria are about in most all aquatic systems...>
**Since this took some time to figure out, it is very likely that I used some tool (a net or whatever) on both the 10 gallon and the 5.5 gallon tanks after the 5.5 gallon was infected.**
I tried treating the 5.5 gallon with Tetra Lifeguard (it's the only medication I had on hand so I gave it a try), which was ineffective against most of the symptoms I was seeing. The number of fish with spinal deformities was going up, and there were several deaths within a few days of each other, so I began to consider euthanizing them.
<I would; yes>
Before I did, however, on July 15 the crayfish molted and was left with at least three exposed gills on one side. They were completely outside the carapace. I went to my LFS (they have a local reputation as "experts"), freaking out a bit, and the guy was worse than useless. He said he couldn't help me, there was nothing that could be done for either the crayfish or the Gambusia. His actual advice regarding the crayfish was, "just keep checking the water conditions and see if she makes it."
<?!>
I euthanized about 15 fish that day, mostly fry, and treated the healthiest ones with Kanamycin. I completely broke down my 5.5 gallon tank and tossed all the live plants, but didn't know what to do about the crayfish in the 10 gallon. I decided to just go on the assumption that crayfish couldn't contract mycobacterium (if that's even what my fish had, but I didn't test them, so I'm not 100% sure), and that the bad molt was due to lack of iodide, which she only really gets from her diet.
<Again; I'd supplement; weekly, add to the water>
The last few months she was pretty much refusing to eat the gel food any more and would just make a mess with it and then leave it sitting on the bottom of the tank. She stopped eating the stuff she usually enjoyed, like fresh kale, and would almost exclusively eat the shrimp pellets or the flake fish food that I put in for the mosquito fish. I kept meaning to buy aquarium iodide to supplement this, but life happened and I never got to it. I didn't realize how long she went without eating greens until I saw the effects.
When she had the bad molt,
<You are leaving these molts in the system I hope/trust, for this animal to consume>
I tried to be more vigilant about water conditions (though when I tested it at the time, the parameters were actually the same as the first test listed above, they weren't horrible, but I hadn't been cleaning the tank as often as I should have been and I wasn't sure if that contributed or not), and tried to get her to eat more green things. Once again, though, several things happened in my life that made it get pushed aside, and she must not have been getting enough iodide still...
She molted 5 days ago and she almost died this time. I found her lying on her side next to her molted exoskeleton, and she had a number of gills outside the carapace again but more this time, and on both sides. One of her antennae didn't look right, and she was not moving. Her little antennules were twitching, though, so I covered the tank with a dark towel
and kept her in the dark and quiet for about 24 hours before checking on her again. At that point she was still on her side, but another 12 hours later she was upright again and eating her exoskeleton. Now I have been able to see her better and not only are a bunch of gills outside her shell and an antenna bent (and the part after the "bend" is turning white), but one of her claws looks really bad, too. She was holding it funny and after a couple days the "elbow" (for lack of a better word) turned very bright red. The redness has spread along that claw and it also looks a little fuzzy, like food that's been left in the tank too long. She isn't very active, she is barely eating her exoskeleton at all, but she does walk
around a little and she is definitely alive and alert. She looks awful though.
<I'd also add a level teaspoon of baking soda/sodium bicarbonate and a "hardness" stone like those sold for turtles in the trade>
I have ordered marine iodide and I am keeping the tank somewhat dark, so she feels safe and hidden, to minimize stress. I bought gallons of bottled water and I **VERY** carefully gravel vacuumed the dirtiest part of the tank (I didn't clean the whole thing because, again, stress. I didn't go too close to the crayfish herself, I let her feel hidden.) and replaced the water (about 50% of the tank) with Crystal Geyser, instead of using treated tap water. I don't know why, it just seemed safer. Maybe that's just paranoia.
<Dechloraminated tap/mains water should be fine. Bottled isn't better for crayfish>
My concern about getting her through this is, can this be caused by mycobacterium?
<Not "caused" per se... or per accidens: that is, not the immediate, direct cause... But bacteria may be playing a secondary role here>
It affects the skeletons of vertebrates, could it affect the exoskeleton of an invertebrate?? Should I take the exoskeleton out at this point? Is it just making water conditions worse as it breaks down?
<I would leave it in... and do what I've mentioned above. Triple dose the I2 now>
I adore this crayfish. She is a remarkable little creature. Can I do anything for her? Is there some medication that would help her recover?
There are things I know I did wrong and will be making an effort to change, but I don't know enough about invertebrate biology to know exactly what went wrong, especially when there are a number of possible causes. I'm attaching a couple pictures of her current condition so you can see what exactly I'm talking about.
Thank you in advance and let me know if there is more information you need.
-Margie
<Welcome. Bob Fenner; who will place this msg. in Neale Monk's in-box for his separate resp.>
Crayfish, molt, Myco- pics      12/14/16

Hello again,
<Marge>
Sorry I forgot to attach the pictures when I emailed you earlier today. I was up late studying for finals so I'm a bit tired lol.
<No worries>
Forgive the reflections off the glass of the tank. Also, I cropped the pictures to reduce their size, so some may be odd proportions. If there are any included here that look weird, they are included because they show something specific, like the gills outside the carapace (which are hard to see because they blend into the rocks) or the antenna that is sad looking. The redness of the claw is obvious, but also if you look closely you'll see the fuzziness... like it's rotting. All these are from the most recent molt that she had about 5 days ago. The first 2 pictures were taken 2 days after molting, the next one where she is on her side was taken yesterday, and you can see how the redness has spread down the claw. In that one she is next to her shed exoskeleton, so excuse any random extraneous body parts.
Thank you again for all your time.
-Margie
<Can't (of course) discern root cause/s here; but do concur the molt is odd/misshapen... Perhaps something missing (deficiency)... I'd add liquid vitamins/HUFA mix to the water weekly as well as to the food mix (like SeaChem's "Vitality" product). BobF>

Crayfish, bad molt, and mycobacterium   Neale's go       12/15/16
Hello WWC,
<Margie,>
This is very long because I want to give as much information as possible. I am a college student working on my B.S. in zoology, so this is exactly the kind of thing that interests me and therefore I have collected a lot of information about the circumstances.
<Understood.>
I have a 10 gallon freshwater aquarium with the following water conditions... the first test is from 5 days ago, and the second is after I did a water change:
First:
Nitrate <20 ppm
Nitrite 0
GH 200
KH 180
PH 7.8
Temp 64 F
<All sounds fine.>
Now the numbers are:
Nitrate <20 ppm
Nitrite 0
GH 150
KH 120
PH 7.6
Temp 64 F
<No major problems here.>
In the tank resides one female crayfish of unknown species and two "mosquito fish" (Gambusia affinis). I have had the crayfish since November 2, 2015 when I accidentally caught her from a pond at my school (I was netting some mosquito fish from the pond to put in an aquarium because I'm just weird like that). She was only approximately an inch long at the time, and almost translucent, with tiny little baby pincers. While reading up on crayfish, I found a recipe for a gel-type food that I could adjust to meet her needs. It uses gelatin as a binder, and is frozen after it sets, so I
can break off cubes to thaw as needed. I made it with dried Spirulina, dried organic kelp, fresh spinach, fresh zucchini, cooked whole shrimp, and some salmon. It is mostly greens, though, as that seemed most appropriate.
Her diet consists of the gel food, shrimp pellets, algae pellets, fresh greens/cucumber/etc., duckweed, and sometimes frozen brine shrimp. I try to keep it varied.
<Good. This all sounds appropriate. Gambusia are a bit hit and miss in fish tanks, but shouldn't cause any problems with crayfish.>
Now she is approximately 4.5" long, and has molted 10 times since I brought her home. The problem started with the last molt, which was July 15, and continued with one that happened 5 days ago. Before I get to that, however, I want to express my reason for emailing you when you have so many posts already regarding bad molts.
<Indeed! It's impossible to know the real problems, but iodine may be a significant factor. On top of that, other dietary deficiencies are possible, but as you suggest, maximising variety, and biasing towards plant foods, probably helps here. Then there's exposure to heavy metals. While clearly copper for example is toxic to crustaceans above certain levels, the problems caused by lower, non-lethal levels aren't often considered by aquarists, but may be important. There may be other factors too, such as day length or season temperature variations we just don't consider, and again, these may be important with regard to properly synchronising all the different physiological mechanisms involved.>
I had some mosquito fish fry in my 5.5 gallon aquarium, and on June 5th I noticed one fry had a bent spine. I thought maybe he had been injured or something, and never considered that it could be something contagious.
<The odd deformed fry is relatively common among fish. They tend to produce large numbers of offspring, but with little of the "error correction" typical among mammals, where deformed embryos will be eliminated long before birth. I guess it's down to the relative shortness of the pregnancy phase, and the far weaker interaction between the eggs and the mother's blood supply. There are exceptions, the Goodeids for example having the equivalent of a placenta, but your Mosquitofish do little more than carry the eggs and provide oxygen; the fry get most of their energy from a yolk
sac, and relatively little from the maternal blood supply.>
Then there were some other anomalies with the fish in that tank and with the tank conditions, the specifics of which probably don't matter in this context. But at some point I realized there were more than one fry with a bent spine, and finally researched it as a symptom of a larger illness, rather than an injury. I began to come to the horrible hypothesis that my tank somehow had been infected with mycobacterium. It explained many of the abnormalities I had encountered.
<Possibly. But Mycobacteriosis is very difficult to diagnose by visual inspection. It's probably impossible to do so, really. It may also be the case that Mycobacteriosis may well be latent in most tanks, but only becomes a problem under specific conditions where fish are stressed or poisoned. In any event, it's hard to say that's the story here, because things like bent spines and failed moults can easily be explained by environmental stress, genetics, dietary shortcomings, etc.>
**Since this took some time to figure out, it is very likely that I used some tool (a net or whatever) on both the 10 gallon and the 5.5 gallon tanks after the 5.5 gallon was infected.**
<Easily sterilised using dilute bleach followed by thorough rinsing.>
I tried treating the 5.5 gallon with Tetra Lifeguard (it's the only medication I had on hand so I gave it a try), which was ineffective against most of the symptoms I was seeing. The number of fish with spinal deformities was going up, and there were several deaths within a few days of each other, so I began to consider euthanizing them.
<Yikes.>
Before I did, however, on July 15 the crayfish molted and was left with at least three exposed gills on one side. They were completely outside the carapace. I went to my LFS (they have a local reputation as "experts"), freaking out a bit, and the guy was worse than useless. He said he couldn't help me, there was nothing that could be done for either the crayfish or the Gambusia. His actual advice regarding the crayfish was, "just keep checking the water conditions and see if she makes it."
<Would agree somewhat; once crustaceans are sick, it's actually very difficult to heal them. On the upside, if fed and protected, subsequent moults can put right any damage.>
I euthanized about 15 fish that day, mostly fry, and treated the healthiest ones with Kanamycin. I completely broke down my 5.5 gallon tank and tossed all the live plants, but didn't know what to do about the crayfish in the 10 gallon. I decided to just go on the assumption that crayfish couldn't contract mycobacterium (if that's even what my fish had, but I didn't test them, so I'm not 100% sure), and that the bad molt was due to lack of iodide, which she only really gets from her diet.
<I would agree with your analysis here, in the sense Mycobacteria species are unlikely to jump from a fish to a crustacean. That said, I don't know that for sure.>
The last few months she was pretty much refusing to eat the gel food any more and would just make a mess with it and then leave it sitting on the bottom of the tank. She stopped eating the stuff she usually enjoyed, like fresh kale, and would almost exclusively eat the shrimp pellets or the flake fish food that I put in for the mosquito fish. I kept meaning to buy aquarium iodide to supplement this, but life happened and I never got to it. I didn't realize how long she went without eating greens until I saw the effects.
<Understood. Their scavenging behaviour does mislead some folks into seeing them as more carnivorous than they really are. Crayfish are more deposit feeders, and tend to consume a lot of algae and decaying plant material alongside carrion and other scraps of food.>
When she had the bad molt, I tried to be more vigilant about water conditions (though when I tested it at the time, the parameters were actually the same as the first test listed above, they weren't horrible, but I hadn't been cleaning the tank as often as I should have been and I wasn't sure if that contributed or not), and tried to get her to eat more
green things. Once again, though, several things happened in my life that made it get pushed aside, and she must not have been getting enough iodide still...
<I see this from your photo.>
She molted 5 days ago and she almost died this time. I found her lying on her side next to her molted exoskeleton, and she had a number of gills outside the carapace again but more this time, and on both sides. One of her antennae didn't look right, and she was not moving. Her little antennules were twitching, though, so I covered the tank with a dark towel and kept her in the dark and quiet for about 24 hours before checking on her again. At that point she was still on her side, but another 12 hours later she was upright again and eating her exoskeleton. Now I have been able to see her better and not only are a bunch of gills outside her shell and an antenna bent (and the part after the "bend" is turning white), but one of her claws looks really bad, too. She was holding it funny and after a couple days the "elbow" (for lack of a better word) turned very bright red. The redness has spread along that claw and it also looks a little fuzzy, like food that's been left in the tank too long. She isn't very active, she is barely eating her exoskeleton at all, but she does walk around a little and she is definitely alive and alert. She looks awful though.
<Agreed.>
I have ordered marine iodide and I am keeping the tank somewhat dark, so she feels safe and hidden, to minimize stress. I bought gallons of bottled water and I **VERY** carefully gravel vacuumed the dirtiest part of the tank (I didn't clean the whole thing because, again, stress. I didn't go too close to the crayfish herself, I let her feel hidden.) and replaced the water (about 50% of the tank) with Crystal Geyser, instead of using treated tap water. I don't know why, it just seemed safer. Maybe that's just paranoia.
<I would be careful dramatically changing water chemistry. Good water quality is important though, and ideally water that's somewhat hard, to reduce osmotic stress if nothing else, but also to prevent further damage to her skeleton.>
My concern about getting her through this is, can this be caused by mycobacterium?
<No idea, in all honesty.>
It affects the skeletons of vertebrates, could it affect the exoskeleton of an invertebrate?
<Completely different mechanisms of secretion and maintenance, so hard to imagine Mycobacteria could affect them/these similarly.>
Should I take the exoskeleton out at this point? Is it just making water conditions worse as it breaks down?
<Crayfish should have access to previous moults; what we do know about crustaceans generally is that consumption of their moult is often significant, and budgeted into their energy equation, allowing them to recycle nutrients. Without access to the moult, they might 'overspend' on calcium or whatever, and that deficit could be lethal.>
I adore this crayfish. She is a remarkable little creature. Can I do anything for her?
<Optimise water quality; offer tiny bits of food periodically; provide a suitable source of calcium such as a bit of cuttlebone to harden the water and possibly be eaten; optimise diet, to include seaweed-based iodine sources.>
Is there some medication that would help her recover?
<The science just isn't there yet. We know almost nothing about medicating inverts. Far more effort is put into exterminating them, insects especially. We probably wouldn't know much about fish medicines either, were it not for hobbyists keeping them as pets. Only very recently has fish farming been an actual thing big enough to warrant research.>
There are things I know I did wrong and will be making an effort to change, but I don't know enough about invertebrate biology to know exactly what went wrong, especially when there are a number of possible causes. I'm
attaching a couple pictures of her current condition so you can see what exactly I'm talking about.
<Thank you.>
Thank you in advance and let me know if there is more information you need.
-Margie
<Most welcome, Neale.>

Re: Crayfish, bad molt, and mycobacterium      6/20/16
Hello again!
<Margie,>
Thank you so much for all the information. As Neale observed, there is a lot more information available out there about exterminating inverts than saving them, so you guys are a rare and valuable resource.
<Thanks for the kind words.>
Since both responses I got asked about this, yes, I do always leave the exoskeleton in the tank every time she molts so she can "recycle" it. (Got a great picture of her eating her own claw once. It was AWESOME. And it creeped my mom out, too, which was a bonus.)
<Heh!>
The crayfish lost her damaged claw the other day. Not just the part that's exoskeleton, either-- there was a good sized chunk of flesh that came off too. She has a little stump that is still bright red and white, and looks quite bad. She hides 24/7 (making it difficult for me to get a good look at her) and barely moves at all. She doesn't explore, or rearrange her tank, or scavenge for food at all. She hasn't been eating her exoskeleton, or anything else that I know of. I kind of gently nudge her tail sometimes just to see if she is still alive (she is). I'm very concerned.
<Understood. Autotomy, the casting off of damaged/trapped limbs, is within the normal range of things crayfish do. So in theory, if the break is clean, she can/will survive without much trouble. But if the damage extends beyond the natural 'breaks' in their exoskeleton, they can quickly become infected. If she survives a week, that's probably a good sign though.>
I removed from the tank the part of her dead claw that was fleshy, after a couple days, since it was beginning to decompose.
<Absolutely! Leaving empty shells to be eaten is good. Leaving decaying hunks of flesh, that's bad!>
I guess my big question is just... in your opinion(s), do you think she will make it? Obviously you can't predict the future (or can you?? o_0) but in your experience is something like this survivable?
<Yes, if the break is clean. Less likely otherwise.>
Also, how much iodine should I be supplementing? Since I usually see the recommended dose is half whatever the bottle says, but then Bob said triple dose, so does that mean triple the half dose (so 1.5x the dose on the bottle label), or triple what the bottle says?...
<Oh, I'd tend to go half the dosage stated for marines. Freshwater organisms seem hard-wired to get by with less iodine.>
Thank you again.
-Margie
<Most welcome. Neale.>

Crayfish plague?    10/28/16
So it's been almost a week of diligently dosing iodine into my p.clarkii ghost's water and I am pretty convinced that it isn't a problem with his moulting because he is still in the same state as before, maybe even less energetic.
<"Post hoc, ergo propter hoc" is something to beware of here! Just because once thing follows another, doesn't mean they're causally linked. In this case, the failure of the iodine to dramatically improve things doesn't mean the iodine isn't helpful or wasn't the issue -- it might simply be too late, or alternatively, things might have got worse without the iodine. So keep an open mind. Iodine is absolutely essential for crayfish, that much is accepted by all the hobbyists keeping them nowadays, especially those keeping expensive and rare varieties.>
I suspect he is having crayfish plague and here's why:
1) His legs twitch uncontrollably as if he has no control over them (did some research and that's a sign of crayfish plague). He cannot even move around to eat anymore so I try to feed him by picking him up, turning him upside down and placing pellets (which I softened by soaking them in water for a few mimutes) on his beak. He initially accepted a bit of the food but now it seems that he has lost his ability to squeeze and chew up the food with his beak.
<This just sound likes a stressed/dying crayfish. Not a symptom of anything else. The clinical tests for Crayfish Plague require examination of the blood and muscle tissues. Obviously if you're an ecologist who comes across a bunch of dead or drying crayfish in a river with otherwise excellent environmental conditions, Crayfish Plague is something to consider. But a single sick crayfish in an aquarium? Nope, Crayfish Plague is kind of like "Swim Bladder Disease" in fish -- i.e., meaningless, and just another way of saying "sick and dying".>
2) On the underside of the tail where his pleopods are, his flesh seems to have become transparent almost to the point where his alimentary canal is fully visible (I think this is another sign of crayfish plague correct me if I'm wrong
<Again, indicative of a sick/dying crayfish. Their tissues do indeed change colour (think about a cooked shrimp versus a live one) but in the case of Crayfish Plague, one common symptom is darkening of the muscles where the legs (pleopods) attach to the body. There are some photos you can find via Google, but I stress, a sick Crayfish will look more or less like this, whatever it's dying from.>
All I can do now probably is to watch him die in his tank, I've probably already done everything I could to save him.
<I agree, but there are a few things left. Substantial, daily water changes. Increase aeration. Check hardness and pH. Don't force feed, but do try and feed every couple of days, even if only a small bit of white fish fillet held in front of the mouthparts. Crayfish are hardy, and have come back from seeming death.>
Even if there's treatment, I probably wouldn't have enough money to buy it for him. This will probably be the last crayfish I keep, unless I can get over this one's imminent death.
<I do suspect you've been unlucky, and will direct you to the excellent PetShrimp.com forum, which has a crayfish section where I think you'll get quick, specific help if you can post photos as well as descriptions:
https://www.petshrimp.com/discussions/viewforum.php?f=3
While I don't agree with this guys on everything (the site owner isn't a big fan of iodine, for example) they're very thorough and helpful people.>
Thanks for all the help that you guys have previously given me though :)
<Most welcome. Neale.>

Blue lobster!! HELP!       8/23/15
So this is Bernie, I love him more than life itself. What's wrong with him?! This thing on his eye started out a few days ago and looked like a spider web and now it's progressed. I'm worried....
Please any info on this eye condition would be wonderful! I think he is completely blind by it now, I just want to know if it's hurting him.
(There's plenty of room in the heart for a special needs blue lobster).
<Let's simplify things by first asking you one question:
What source of iodine are you providing your crayfish?
If the answer is "none" then that's likely your problem. Crustaceans, particularly the bigger ones like crabs and crayfish, need a supply of iodine to moult properly. Without it they suffer from all sorts of
developmental problems, and sometimes simply die. Since crustaceans can "self repair" with each new moult, providing iodine can fix some developmental abnormalities, though typically over a series of moults rather than just one. It is possible your crayfish is suffering from an infected wound, bad genes, or exposure to a toxin such as heavy metals (copper, most commonly; a good marine aquarium store can check your tap water copper concentration for you). But even with these, providing iodine would ensure your crayfish has the best chance of fixing itself. You can buy iodine supplements from marine aquarium shops, and dosing at half the amount stated on the package is normally ample for freshwater tanks. In marine tanks it's SOP to add iodine as often as daily, but once or twice a week should be more than adequate for freshwater crayfish. In addition, providing iodine-rich foods such as seaweed (Sushi Nori for example) and certain crayfish/crustacean specific foods enriched with iodine. These will give your chap a quick boost of iodine that may stimulate moulting and repair. Neither the iodine supplement nor the Sushi Nori are expensive, so you shouldn't find any of this too onerous. With luck, you'll see your crayfish patch himself back together across the next few moults. That's the theory, anyway! Cheers, Neale.>

Please help with my yabbie      5/29/15
Hi
<Howdy>
I have a blue yabbie 'pepper' that I've had for about 7 months now and he's very much loved. He's been looked after and has been doing very well. 21l tank plus filter plus an air rock with water changes every 2-3 weeks as it's needed.
<Umm; what re water quality, feeding... Iodide/ate use?>

I just came home today to find him lying on his back with his tail curled up dead. I've had him since he was little and I have no idea why this has happened when he's been so well? There are no markings on him anywhere.
What's happened and what can I do to prevent it.
<Highly likely a simple nutritional deficiency at work here; or a water quality/environmental one...>

Please I would really appreciate your help
<Have you read here?
http://wetwebmedia.com/CrayDisDiagF.htm
and the linked files above? Bob Fenner>

ghost lobster questions; sans data        3/19/15
i have a ghost lobster that is around 4 inches in length. His head is turning brown. Seems healthy, eating great, active and night as usual. So see no change in behavior. Just want to make sure there is nothing to worry about. Was wondering if they may change color some when getting ready to molt.
<Mmm; might be "nothing"; but the color change could be evidence of something off with water quality (which you give no indication of) or nutrition (ditto). READ on WWM re Crayfish Systems and Feeding. Do you need help using the search tool, indices? Bob Fenner>

 

do Louisiana crawfish hibernate in captivity      11/17/14
My daughter rescued a crawfish from a crawfish boil last May - about 6 months ago. We keep Isabelle (the crawfish) in a 10 gallon tank, filter, gravel, half full and a hiding place.
<Neat! I "did this" also... with likely the same species, Procambarus clarkii; as a college student studying this animal's substrate preference behavior>
We feed her mostly the pellets and occasionally some veggies. She seemed to be doing okay. Had some eggs, but lost them.
<Not fertile if solitary>

She molted a month ago and seemed fine. Last week she was on her side. We flipped her over. Today she's seems virtually dead. Hardly moving.
<Mmm; very common... usually an issue of nutritional deficiency, particularly a bit of iodine/ide... or usable iron... Search, read on WWM re... or write back if you can't/don't figure out how to use our indices or
search tool>
At one point I thought she was dead, but in a shallow bowl of water (to observe her) the water kept circulating so she is clearly still breathing.
It is November - is she beginning some sort of hibernation?
<Mmm; not likely if indoors... i.e. kept where warm>
Could this be nutritional?
<Yes; almost assuredly>

We didn't know to keep the exoskeleton in the tank, so she lost out on that. I'm wondering if I need to be in emergency-doctor mode or hospice nurse mode. Help!
<Can be rescued likely by application (to the water) of the above... there are commercial prep.s for aquarium use... or one can assemble DIY>
Thanks for your site, it's really the only place to find good info about keeping crawfish as pets (though I wish I hadn't overlooked the part about leaving the exoskeleton in the tank!)
Thank you,
Pamela Berg,
Northbrook, IL
<Please do write back if any of this is incomplete. Bob Fenner>
do Louisiana crawfish hibernate in captivity
     11/17/14
My daughter rescued a crawfish from a crawfish boil last May - about 6 months ago. We keep Isabelle (the crawfish) in a 10 gallon tank, filter, gravel, half full and a hiding place. We feed her mostly the pellets and
occasionally some veggies. She seemed to be doing okay. Had some eggs, but lost them. She molted a month ago and seemed fine. Last week she was on her side. We flipped her over. Today she's seems virtually dead. Hardly moving. At one point I thought she was dead, but in a shallow bowl of water (to observe her) the water kept circulating so she is clearly still breathing. It is November - is she beginning some sort of hibernation?
<Nope. Just to be clear: only warm blooded animals, specifically mammals rather than birds can hibernate. For sure some cold blooded animals become torpid but they don't actively lower their temperature or metabolic rate -- they are simply forced into a situation where ambient coldness makes their metabolic rate slow down. So, if you're talking about crayfish, they'll be as active as ambient water temperature allows, and indoors, that's pretty
much optimal all year around so far as North American crayfish species go.
Put another way, unless the tank is frigid-cold then it's very unlikely a cold blooded crayfish would be deliberately slowing down in the same way as a hibernating dormouse.>
Could this be nutritional?
<Immeasurably more likely.>
We didn't know to keep the exoskeleton in the tank, so she lost out on that. I'm wondering if I need to be in emergency-doctor mode or hospice nurse mode. Help!
<Optimise water quality and chemistry as per normal, but also use iodine drops (sold for marine tanks, used at about 50% the quoted dose). Iodine is the "wonder drug" for many crustaceans because it's lacking in their diet
when given generic aquarium foods. Providing iodine prevents all sorts of problems, and in some cases, can undo damage. Crustaceans, like molluscs, tend to exist in a binary state under aquarium conditions -- they're either
thriving or dying, with not much in between. Do start reading perhaps here:
http://www.wetwebmedia.com/fwsubwebindex/crayfishdisfaq.htm
Links to various articles and FAQs at top.>
Thanks for your site, it's really the only place to find good info about keeping crawfish as pets (though I wish I hadn't overlooked the part about leaving the exoskeleton in the tank!)
Thank you,
Pamela
<Glad to help. Cheers, Neale.>
Re: do Louisiana crawfish hibernate in captivity
     11/17/14
Thank you so much. I'm off to the aquarium shop to get marine iodide (iodine?) and better food (and a new filter). Didn't realize how much all we loved this little girl until we thought we lost her.
<Ahh; a good life lesson. BobF>
Re: do Louisiana crawfish hibernate in captivity
     11/18/14
Hi Bob,
We changed her water and added the .25tsp of marine iodine (it said 2 tsp per 50 gallon and our tank is 10 gallon). The person at the local aquarium shop said the calcium in our hard water is probably good for her too
<Yes it is>
-- and she did almost instantly perk up.
<Ah yes; the I2... miraculous in appearance eh?>
Last night she was crawling all over, trying to escape -- very uncharacteristic of her, though I've read on your site how they can be real escape artists, so we were very hopeful, almost giddy with excitement. We thought it was a real miracle -- my husband called her Lazarus.
<Ooh, a fave character in the R. A. Heinlein books he shows up in>
This morning she was on her back and motionless, though after I flipped her I can see she's not dead. She is not eating -- even last night as her little alien gill-like belly button of a mouth was going bonkers, she would
not eat any of the food we put in the tank -- bottom crawler pebbles, lettuce, algae tabs, a frozen pea. I thought about putting a few small fish in there to stimulate her and maybe she'll eat them. Or get some fresh plants?
<These would help... and just a drop more iodide-ate every other day>
Thanks for your help-- and any more advice you might have.
Pamela Berg
<Reading (on WWM, elsewhere re Crayfish) and patience. Bob Fenner>
Re: do Louisiana crawfish hibernate in captivity      11/18/14

Bob,
Thanks for all your advice. I made a small donation to your wonderful website/organization.
Pam
<Ah; thank you. B>

Some Help- Crayfish; the usual lack of data     12/7/13
Hi,
My name is Christa and I have a crayfish that is  slate colored and lives in a 20 gallon with water ranging between 78-82 degrees.
<... what species is this? This temp. is too high for non-tropical>

 I have notice his right eye turning color after his molt about a month ago and now his eye has some huge white ball formation over it. I do not know what it is or if he will die from it.
I would like some help on this,
Thanks
<Hopefully not die; but need information... re the set up, water quality, and nutrition. Most Cray species kept by hobbyists need hard, alkaline water, and regular iodide-ate additions to the water... Read here:
http://www.wetwebmedia.com/CrayDis4.htm
and the linked files above. Bob Fenner>
Re: Some Help- further blather sans reading    12/8/13

I really have no idea what species he is. He's about 4 inches long. He's been living in my tank with that temp for half a year already with no problems. But if it's best to put him in colder water, then I can move him to a small tank. It would be best right?
<Assuming you didn't pay a (very) premium price for one of the Australian species (Cherax spp.), then you have one of the standard issue US species, usually Procambarus clarkii or else (usually less commonly) Procambarus alleni. As you'd expect for species native to the southeastern United States, they are both room temperature species. Survival for about half a
year before things go wrong is actually very common -- and my guess would be that a moult is long overdue, but lack of iodine in the diet has prevented this from happening. As Bob suggests, get some marine aquarium iodine drops (not expensive) and use at 50% the dose recommended on the packaging (so it's even less expensive). Beyond that, a mixed diet
including Sushi Nori (rich in iodine) and occasional unshelled shrimp and krill (rich in calcium) will be useful, alongside a predominantly greens-based diet (algae wafers, cooked peas, softened vegetables).
Basically crayfish are easy to keep for a few months... the real art is keeping them across several years! Cheers, Neale.>
Re: Some Help-    12/9/13

I have moved my little guy to my 10 gal tank. The little bit of water is room temp. And I do throw in algae wafers and shrimp pellets. Thanks for the help!
<...I2? Read where you've been referred. B>

Sudden Death of Procambarus clarkii     3/25/13
<... we have a limited amount of space w/ this webmail prog.. Ask that people in turn only send a few hundred Kbytes... yours is about 8 meg.s...>
Dear WWM team,
<Cath>
About a week ago I purchased two Procambarus clarkii (I think that is what they are - see attached cell phone photo - excuse the blurriness) from a local supplier from which I had purchased my two Cherax quadricarinatus (Lucille and Luigi) who are absolutely thriving (see other attached photos).
<Very nice>
I have had Lucille for nearly a year now and Luigi for about 4 months.
Luigi and Lucille are kept separate to each other and separate to the two new lobsters. I was devastated when less than a week later, both my new babies were dead.
<Mmm>
I admit that I was probably a bit hasty and did not prepare the tank properly for them but all seemed well for the first few days. I cleaned the tank thoroughly prior to bringing them home - the day before purchase. I have a sponge filter to keep the water clean, use a dechlorinator that removes chloramines and chlorines and the temperature is kept at about 24 degrees Celsius by means of a heater (not really necessary in our climate!).
The white lobster (Pepper) was fractionally smaller than the red one (Chili) (+/- 4 to 5cm) but this did not seem to cause any major issues.
The tank had plenty of little hiding spaces for them to retreat to. Pepper was the first to die. "He" was fine at feeding time (using the Tabimin Bottom Feeder tablets) and then the next morning I awoke to find him lying dead on the tank floor. I quickly removed him and put it down to the fact that he was smaller and maybe had gotten bullied by Chili or that perhaps the shock of moving was too much for him. This was two days after purchase. I had a good look at him and did not see any lesions or obvious abnormalities.
About three days later, I went to feed Chili. I dropped the Tabimin piece in the tank and waited. "He" did not appear as usual. At first I thought he had escaped (irrational as the tank has a lid) but eventually found him burrowed down in the gravel under one of the ornaments. I must mention that when I brought him home I noticed that one of his pincers was missing a "prong" and that one of his legs was also "amputated". This didn't really bother me as I know that they are capable of regeneration. He also had one or two tiny brown/black spots on his shell and one or two on his legs.
<As you state; should be of no consequence>
Basically my question is - do you think that this was simply a case of being too hasty and not preparing adequately?
<Could be these co-mortalities are coincidental; but better to further consider whether there is something amiss here; perhaps w/ the system, water quality>
 Or could the broken pincer and brown spots mean something? I had a good look at Chili's corpse and nothing seemed untoward (I work at a veterinary pathology lab - was contemplating performing an autopsy!).
<If you think it might prove fruitful... better some base knowledge and a mass spec. sampling of a few tissues methinks>
My Cherax lobsters are absolutely thriving so that is why I am puzzled as to why the other two died so suddenly. I also want to make sure that they didn't have anything that could be passed on to my other two.
Kind regards,
CATHERINE
<Is there an ornament present in this system? Some source of metal (the Cherax may have become habituated)... I'd be running a pad of Polyfilter in the water/filter flow path to look for color... and have you read here:
http://www.wetwebmedia.com/CrayDis4.htm
and the linked files above for insight/s. Bob Fenner>

Chili and Pep
Lucky Luce & Luigi

Red Growth On Eyes (Cherax Destructor) (photos attached)  2/1/13
To the Crew
<Em>
I think my pet yabby (Cherax destructor) is suffering from some sort of parasitic infection.
<Mmm, looks more like a deficiency syndrome of some sort; that or an over-abundance of something that is "burning" this animal>
 For quite some time he’s had some brown diatoms on his exoskeleton, I didn’t think anything of it because I was having an issue with the algae at the time,
<... are you treating the water w/ some sort of chemical/s?>
but he seems to have some sort of bright red growth on his eyes. It’s definitely impairing his sight, because things like camera flashes which used to greatly disturb him no longer have any effect. He seems to be eating less, but I don’t know if it’s because of a loss of appetite or because he’s having trouble finding the food before the fish hoover it away. He seems to be less mobile, spending much time with his tail curled, but when he does move the movement seems natural.  He doesn’t seem to groom as often as he used to. He has strange ring like growths on his claws and the tips of his legs seem off colour, but this may be algae. I don’t know the exact water hardness but there is coral rubble and seashells in the water so it should be reasonably hard and alkaline.
<... need to know, have adequate biomineral content (Ca, Mg... and alkalinity) as well as periodic administration of Iodide-ate. Have you searched, read on WWM re?>
I live in Australia so crayfish plague shouldn’t be possible, but I can’t find any other diseases known to affect yabbies.
He’s in a 175 litre aquarium, with a sand substrate, an Eheim pickup 2012, an aqua one wet and dry filter, and a Jager heater that keeps it at 26 degrees Celsius. There are also several Darwin red nose shrimp, 9 black banded Rainbowfish, three salmon red Rainbowfish and one bristle nosed catfish in the aquarium with him. The tank has been set up and cycled for around 9 months, and I haven’t had any issues until now. He has a shelter from the light made from Mopani wood arranged as a cave. He’s 20cm long with his claws and tail fully extended, and I suspect him to be quite old. He’s moulted once while I’ve had him, because of his size I didn’t think much of it.
I’ve had him for over a year now and I’ve grown very attached to him. I’m going on a trip overseas in two days and will be leaving him with a house sitter, and I have no idea what I can do for him! I’d hate to lose him and I feel that I need to do something for him, as he seems to be near blind and unhappy. I have obtained an iodine supplement and will start dosing right away, and I’ll leave a note instructing the house sitters to dose him while I’m gone, but they have no experience with aquariums of their own and I don’t want to ask too much of them.
Kind regards, and thank you in advanced.
EM
P.S. I'm very sorry to have emailed this twice, but I took some photos and forgot to attach them, I've attached them now and I hope they'll help you. Thank you for your patience.
<Read here: http://www.wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm
and the linked files above. Bob Fenner> 

 

Red Growth On Eyes (Cherax Destructor)   2/3/13
To the Crew
<Em>
I think my pet yabby (Cherax destructor) is suffering from some sort of parasitic infection.  For quite some time he’s had some brown diatoms on his exoskeleton, I didn’t think anything of it because I was having an issue with the algae at the time, but he seems to have some sort of bright red growth on his eyes.
<I wrote you re this issue a day or two back... Have you read where you were referred?>
 It’s definitely impairing his sight, because things like camera flashes which used to greatly disturb him no longer have any effect. He seems to be eating less, but I don’t know if it’s because of a loss of appetite or because he’s having trouble finding the food before the fish hoover it away. He seems to be less mobile, spending much time with his tail curled, but when he does move the movement seems natural.  He doesn’t seem to groom as often as he used to. He has strange ring like growths on his claws and the tips of his legs seem off colour, but this may be algae. I don’t know the exact water hardness but there is coral rubble and seashells in the water so it should be reasonably hard and alkaline.
<Need to have water test kits, or others test for you>
I live in Australia so crayfish plague shouldn’t be possible, but I can’t find any other diseases known to affect yabbies.
He’s in a 175 litre aquarium, with a sand substrate, an Eheim pickup 2012, an aqua one wet and dry filter, and a Jager heater that keeps it at 26 degrees Celsius. There are also several Darwin red nose shrimp, 9 black banded Rainbowfish, three salmon red Rainbowfish and one bristle nosed catfish in the aquarium with him. The tank has been set up and cycled for around 9 months, and I haven’t had any issues until now. He has a shelter from the light made from Mopani wood arranged as a cave. He’s 20cm long with his claws and tail fully extended, and I suspect him to be quite old. He’s moulted once while I’ve had him, because of his size I didn’t think much of it.
<This is very little moulting behavior... likely indicative of more than just age... Likely a water quality and/or nutrition imbalance issue>
I’ve had him for over a year now and I’ve grown very attached to him. I’m going on a trip overseas in two days and will be leaving him with a house sitter, and I have no idea what I can do for him! I’d hate to lose him and I feel that I need to do something for him, as he seems to be near blind and unhappy. I have obtained an iodine supplement and will start dosing right away, and I’ll leave a note instructing the house sitters to dose him while I’m gone, but they have no experience with aquariums of their own and I don’t want to ask too much of them.
Kind regards, and thank you in advanced.
-EM
<Just in case our previous email was lost, please read here: http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
and the linked files at the bottom. Bob Fenner>

Black Spots on Crayfish  1/1/13
Dear WetWeb Media Crew,
My 3-year-old crayfish has two black spots just above his eyes, on his carapace. I wouldn't be worried about except one of my other crayfish died two months ago and that crayfish, who had the same marks, died molting. Are these marks shell rot and something I should be worried about? They are pink in the center and almost look a bit raw, but are rimmed by black and don't look like any images of shell rot I've seen before. I am attaching a few images of my crayfish, Slippy. Hopefully you can help me figure out if something is wrong. Thank you. (Ignore the white spots in the water, that's the light reflecting.)
<This crayfish doesn't seem to be damaged or suffering, so I'd not worry overmuch. But do review two key aspects: diet and water chemistry. So far as diet goes, make sure you are providing both calcium (e.g., whole krill) and iodine (e.g., Sushi Nori or marine aquarium iodine drops at 50% stated dosage). For water chemistry, make sure the pH is above 7 otherwise the shell will tend to erode over time. Since crayfish moult less the older they get, older specimens show this type of shell erosion worse than young specimens. Do review the page linked below, and follow the links at the top to useful articles:
http://www.wetwebmedia.com/fwsubwebindex/crayfishdisfaq.htm
Cheers, Neale.>
<<Excellent concise direct response Neale. Well done as usual. BobF>>

Re: Black Spots on Crayfish    1/3/12
Thank you so much for clearing this up for me, I wasn't sure and I haven't seen it anywhere else online. I'll have to go by some Nori for the little
guy.
<Most welcome. Iodine drops will likely work out cheaper, more effective in the long term. But Sushi Nori can work if used regularly. Cheers, Neale.> 
Re Black Spots on Crayfish  1/18/13

My crayfish just shed, and he has these huge bulges in his shell and where they are on his shed there are these holes where I can see straight into the shell. The holes were white, but it didn't look like shell rot though I was worried it was. How can I help fix this? I'm really worried because of these lumps.
<Not much you can do at this point! If it can sort itself out, it will.
Ideally, allow the crayfish to consume its moult and then hope for the best.>
I've attached pictures below:
<I see.>
Any helps or tips on what to do would really be appreciated. I meant to feed the little guy some Nori but for a week and a half he only wanted to eat his food pellets. Thank you so much.
<You can buy crayfish and crab specific foods (e.g. Sera Crabs Natural) and these should go a long way to ensuring a balanced diet. Seafood generally is good: unshelled shrimp, mussels, etc. Using an iodine supplement (sold for marine tanks) at 50% dosage seems to work wonders at ensuring good, regular moults. Cheers, Neale.>

Black Spots on Crayfish - 1/25/13
Hi WetWeb,
I found my crayfish on her side this morning, only moving her swimmerets and occasionally a leg. It doesn't look as though she's about to shed, and her limbs are all kind of rigid. Is there anything I can do to help her?
I've checked, and she doesn't appear to have any worms or soft spots in her shell. Her eyes are still clear. I don't have a pump, but I do regular water changes, and what she swims in I drink. What can I do?
Thanks for any help.
<Can you tell me what source of iodine you are using? And at what dose?
This is a key thing with crayfish care. By the time problems develop, there's almost nothing you can do, though adding another dose of iodine may help. Certainly don't try pulling at the moult or anything like that. Do also check water quality; without a pump, how is this aquarium filtered? No matter how pure the water you add, it does need filtering unless you're
changing 50% of the water every day. Cheers, Neale.> 

Irregular spots growing on crayfish     7/4/12
Hello there! I have had a blue crayfish with a small guppy for about a year now. He has a 20 gallon tank with sand substrate, a filter and 2 hiding spots. He eats algae wafers and on occasion, blood worms. His water temp is at about 70-73 F. He is very playful, barely ever hides and actually seems to crave interaction. He has molted at least 5 times since I've had him, but last time (about 3 weeks ago), he came out with a small, bright red spot on his head. Over time, the bright red has turned into orange/brown splotches. She has two more tiny dots like that on her tail. I did some research, and it said this might happen during molting.
<Mmm, yes; quite common... do leave the old molts in place (they're reincorporate)... And one needs to be aware of the alkaline earth, alkalinity needs.... and use/dose a modicum of iodide-ate occasionally. All revealed by your reading here:
http://www.wetwebmedia.com/FWSubWebIndex/crayfishdisfaq.htm
and the linked files above>
He has not molted again since, but I have noticed that there are more, small spots and it looks like they are growing right at the junction of the head plate and his back. The blue color in that ridge is darker than the rest of his body and the spots are growing over the dark blue. His appetite and behavior do not seem to have changed, but this has never happened to him before. I love my Cray and he's always been in optimal health! Please help. What can I do?! Is this shell rot?? I attached a picture of the spots.
Carolina
<The reading... water quality, nutrition. Bob Fenner>
Irregular spots growing on crayfish. Neale's go      7/4/12

Hello there! I have had a blue crayfish with a small guppy for about a year now. He has a 20 gallon tank with sand substrate, a filter and 2 hiding spots. He eats algae wafers and on occasion, blood worms. His water temp is at about 70-73 F. He is very playful, barely ever hides and actually seems to crave interaction. He has molted at least 5 times since I've had him, but last time (about 3 weeks ago), he came out with a small, bright red spot on his head. Over time, the bright red has turned into orange/brown splotches. She has two more tiny dots like that on her tail. I did some research, and it said this might happen during molting. He has not molted again since, but I have noticed that there are more, small spots and it looks like they are growing right at the junction of the head plate and his back. The blue color in that ridge is darker than the rest of his body and the spots are growing over the dark blue. His appetite and behavior do not seem to have changed, but this has never happened to him before. I love my Cray and he's always been in optimal health! Please help. What can I do?!
Is this shell rot?? I attached a picture of the spots.
<Do have a read here first, the Disease section, and check your environmental conditions with the ones you're providing.
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
Understanding of crayfish disease (indeed, of crustacean healthcare generally) is minimal, so prevention is the main way forward. Do check water chemistry (hard water is better) and that you provide calcium in the diet (squished snails, unshelled shrimps/krill and small whole fish such as lancefish -- not feeder fish though!). Do also ensure you're providing regular iodine, in the form of marine aquarium supplement (at 50% dosage) with each water change. There are specific crayfish foods with added iodine, and these are worth using too. There are a few more-or-less harmless parasites that infect crayfish and cause damage to their shells, but given sufficient calcium and iodine, crayfish can moult successfully and effectively minimise this damage. Once crayfish reach a certain age (around 2 years for the common Procambarus clarkii) they moult infrequently, if at all, and very old specimens will naturally have tatty shells, encrusted with algae and suchlike, but their shells are still strong and firm, unless the crayfish is kept in soft, acidic water that dissolves away the shell. Cheers, Neale.>

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

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.
Alexandra
<What re water quality, maintenance...? Read here:
http://wetwebmedia.com/FWSubWebIndex/crayfishfdgfaq.htm
and the linked files above. Bob Fenner>

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

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,
Brett
<Hope your clawed friend is holding in there>
<Benjamin>

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,
Brett
<? 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:
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
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.
Thanks
<Good luck, Neale.>

Is out crayfish dead? 4/21/09
Hello and thank you for your help.
<Hello!>
My daughter brought home a crayfish from school about 4 months ago.
<Cool.>
We found him upside down in his tank last night.
<Oh.>
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:
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm>
I don't want to dispose of the poor little guy if he really isn't dead.
<Indeed not.>
Thanks again for your help.
Susan
<Cheers, Neale.>

Turning brown with white spots on claws 4-13-09
Hello,
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
Brandon
<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:
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
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 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.>

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>

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>

 

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>

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>

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.>

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>

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