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Crayfish, Crawdads, Yabbies, Ditch Bugs Social 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, Infectious, Parasitic,

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,


Red Crayfish with Milky White Eyes?   2/3/13
Hello, I came across your website and noticed there was a lot of information but I could not seem to find information about my particular problem. I have a red crayfish in a 75 gallon tank with about 18 cichlids. Today, his eyes I noticed turned milky white.
<May simply be pre-moulting if this really did appear out of nowhere. But physical damage can cause the eyes to cloud over too; cichlids in particular "go for the eyes" when attacking (as do many fish, which is why eye spots on the tail as decoys are so very commonly seen among fish). Physical damage to the eye won't get better, but it will be removed and replaced with healthy tissue once the crayfish moults. Regardless, isolate the crayfish in its own aquarium for 2-3 weeks. Put a flowerpot in there for a cave, but otherwise leave the tank nice and clean. As ever, dose with iodine supplement (as sold for marine aquaria) at 50% dosage to ensure a proper moult.>
It is a community tank of Central American cichlids and African cichlids.
<Not a recommended mix, but can work if you choose species carefully.>
I have read info on the type of water parameters you need for these guys, and realized it is not perfect for him...The temp is 78, the pH is about 7.6, the KH is about 6-7 drops (Think that is in the 100-125ppm range) Ammonia, Nitrites are zero. Nitrates are about 40 (I know this is considered high, I am going to do a large water change) I have an Emperor 400 filter, two powerheads for water circulation and two airstones hooked up to an air pump.  I try and feed him a sinking algae wafer once a day, also sometimes at night instead of during the day but I often times have a problem with another fish getting to it first and taking it.
<A good clue he doesn't belong here.>
Or, if the crayfish does get it, I have a Jack Dempsey cichlid come in and steal it from him occasionally, right out of his little claws.
I did read today on your website that I need to add iodine into that tank. Could you tell me why this is exactly?
<You're looking for products such as Salifert Natural Iodine, Kent Marine Iodide, Seachem Reef Iodide, etc. Typically inexpensive products, $5-10 a bottle. Dose at half the stated amount on the bottle, so very economical.>
The marine iodine I read increases algae growth, which I do not actually want.
<In a cichlid aquarium without live plants you will battling algae anyway thanks to the high nitrates, so iodine won't make any perceptible difference.>
He has not increased in size in over 4-6 months, thus, he has not gone through a molt yet.
<Again, a good sign he doesn't belong.>
This also I know is a bad thing. Is it the water parameters mostly being off? Aggression from fish maybe attacking him? Stress? Not enough food? No iodine?
<Some combination of these. Crayfish are best kept alone, and contrary to what many beginners suppose, they aren't suitable "critters" for tanks filled with aggressive cichlids. Because crayfish are so easy and cheap to care for properly, there's really no excuse to keep them in community tanks. A 10-gallon tank, a basic filter and a flowerpot are all you need for a singleton!>
Could you provide me with information as to why his eyes changed color like that? Is he actually blind now? (It kind of seems like it, because he does not raise up his claws when a fish is nearby, like he can't even tell they are there?)
<His vision may be blocked, yes; crustacean eyes are compound eyes, but unlike our eyes, they have the exoskeleton over the top of them. So when the exoskeleton gets damaged, it clouds over -- there's no eyelids that can be opened up like our eyes. They're basically looking through a window all the time, but on your crayfish, the window is opaque.>
Thanks for your help, I hope I can hear back from you soon, as I consider his health a real concern. I understand I might need to give him away to someone who can provide better water conditions…
<Much information here:
No real art to keeping crayfish properly if you understand the basics. Cheers, Neale.>
Re: Red Crayfish with Milky White Eyes?    2/4/13

Thanks for all the info. I noticed something interesting the other day when I went downstairs. He actually dug himself a deep hole in the gravel, and literally blocked off the two entrances into where he is with gravel, as if he intentionally was planning to protect himself from intruders. This leads me to believe that he is planning for a molt soon. Should I leave him be there?
<Ideally, yes.>
Or should I disturb where he is and take him out into a freshly set up 10 gallon tank (This other tank hasn't been cycled yet, but I tested for the usual things and all is well, nitrates are really low and no ammonia/nitrites. Temp and pH is the same as my main tank)
<Put him in whichever tank has the mature filter. Moving a crayfish at or immediately after moulting isn't a great idea though. If you must, drive it into a plastic container, lift it out with some water, then release it into the new tank. Don't try to carry the crayfish with your fingers or lift it out of the water with a net.>
I kinda feel like he will be safe where he is. Does the molt happen overnight?
<Pretty much.>
If so do you think the fish will smell his exoskeleton and go in and eat it than possibly attack him when he is vulnerable?
<Does happen, hence crustaceans going into burrows at this time.>
If he is in the process of molting, will it be safe to take him out and move him into a new tank during this process? Thanks again for the info.
I'll go see if my local fish seller has the marine iodine I need soon.
<Cheers, Neale.>

Lost an eye 12/8/11
Our blue crayfish was in a fight with one of our bigger fish
. Although they both got a piece of each other, the crayfish has lost an eye. Any thoughts or ideas on what will happen to him?
Thx. Jenn
<Hello Jennifer. As I've said many times here at WWM, crayfish and fish don't mix. One way or another, someone comes out of this badly. I've seen crayfish catch and eat fish, and I've seen fish damage crayfish (especially after moulting, when their shells are still soft). There is no reason to mix crayfish and fish together, and this is something you'll see stated in all the fish books and magazines. So, the obvious thing is to separate them now. As for the eye, it'll heal over but probably won't re-grow. It won't cause him any serious problems so long as his other sense organs are intact, e.g., his antennae. Cheers, Neale.>

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

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

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

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

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

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