Crayfish, Crawdads, Yabbies, Ditch
FAQs on Crayfish Disease:
Crayfish Health 2,
Crayfish Health 3,
Crayfish Health 4,
Crayfish Health 5, Crayfish Health ,
FAQs on Crayfish Disease by Category:
Crawfish Pie, Let's Make a Crawfish Tank! By Gage
Harford, Invertebrates for Freshwater
Aquariums by Neale Monks,
Freshwater Shrimp, Crayfish,
Freshwater to Brackish
Freshwater Invertebrates/Use in
Aquariums, Freshwater Crustaceans for the Aquarium,
Fresh to Brackish
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
<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
The marine iodine I read increases algae growth, which I do not actually
<In a cichlid aquarium without live plants you will battling algae
anyway thanks to the high nitrates, so iodine won't make any perceptible
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?
<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.
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?
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
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.
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?
<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,
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
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
<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
<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
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
.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
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,
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>