Please visit our Sponsors
Crayfish, Crawdads, Yabbies, Ditch Bugs Infectious Disease

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: Diagnosis, Environmental, Nutritional, Trauma, 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,

Crayfish translucent growths        10/7/17
Good day!
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.
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!!
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; hlth., infectious; no pic          5/22/15
My name is luck
I would like know crayfish marron or Cherax Tenuimanus have Aphanomyces astaci or not????
<Judging by? Looks, behavior? Have you read the wiki coverage:
Bob Fenner>

Re: Health Concerns with Blue Crayfish    5/1/12
Hi again Bob,
Thanks for all your help in the past. Our blue Cray seems to be feeling better now. Water levels have been stable for about three or so weeks now.
She's stopped laying on her side and looking miserable. We think she may have just been in the process of laying her eggs when we saw her appearing so uncomfortable. Her eggs are still black and she's retained all of them on the underside of her tail. She's been eating every few days and is fairly active. We're assuming that the eggs are unfertilized, but we'd read that if they're unfertilized that crays will often drop them. She hasn't dropped any yet and is very protective of them, so we're not sure what that means.
Recently we started noticing that some of the eggs were turning a pinkish orange color and developing a fungus-looking cloud around them. She still has black eggs that appear unaffected by this, but it definitely is spreading, as now she has several large clumps of these orangish eggs coated in a soft white fuzz. Are we correcting in assuming that her eggs have fungus?
<Likely so>
If so, why hasn't she dropped her eggs by now, since they're likely infertile and diseased?
<Sometimes they become so sticky, they stay in place>
I've been researching fungal infections and treatments for invertebrates and some of them sound just plain scary! From what I've read Methylene Blue seems really messy, dyes everything, and can mess with the balance of the cycle - which is exactly what we don't want - and also seems to be best for dips. We're not sure if that's the right solution for her.
<No treatment at all>
 I've read that Malachite Green can be highly effective against fungus, but dangerous and deadly to invertebrates. Is this true?
 If so we certainly don't want to use it for our blue Cray, and that would also nix out SeaChem Paraguard as it contains Malachite Green. Interpet Anti-Fungus looked like it might be an option, but is hard to find in the USA and we want to start her on treatments right away.
The options that look the most promising are Esha2000, Mardel Maroxy for True Fungus (is there a difference between fungus and true fungus?),
<Yes; most of what people label "funguses" are actually bacteria... need microscopic examination to tell>
 Mardel Maracyn-Oxy (non-antibiotic), and Mardel Maracyn Powder or Tablets (antibiotic). From what I've read they all appear to be non-toxic and safe for invertebrates, and they all appear to treat fungus. Aside from that, I have no idea what the difference is between all those Mardel products, I don't know if we should be looking for an antibiotic or non-antibiotic treatment, and I have no idea which ones would be best or recommended. Any suggestions?
<Yes; to not treat period>
Also, now that the eggs have fungus, at what point will they fall off or will she drop them or pick them off?
<Will be shed w/ the next moult>
Will the anti-fungal treatments help this problem, or should we do something to scrape the eggs off of her? Is there a safe, non-traumatizing way to do this?
As always, thanks for your help!
P.S. I have also attached a few images of her with the fuzzy eggs.

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

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

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

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

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

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: