Crawdad Daredevil – 10/22/09
Good afternoon-
<Hello,>
I am a teacher and a few days ago one of my students brought in a crawdad as a classroom pet. I, of course, accepted but have no clue what all is entailed in the care of a crawdad and have been doing my best to keep him happy. As of right now, he is in a 10 gallon aquarium (I was told this was the size needed for a single crawdad), the water level is much higher than he is used to (about 6 inches), there is a cave he has to hide in, and an aerator. He was in a little carrier and, from what the student told me, had been living in about 2 inches of water, with some gravel, and kept in a dark corner.
<Right. Now, do take a look at this article; it covers all the basics:
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
Crayfish are basically tough, easy-to-keep herbivores. The main problems with them are aggression and their intolerance for copper (a trait shared with other crustaceans).>
Since placing him in the bigger aquarium, he has been running back and forth like a jack rabbit, climbing on the cave, pushing it away from the walls of the aquarium, and seeming like he is trying to find the surface of the water. The other thing is he keeps attacking the aerator. This morning I came him to find he had moved the gavel to form a hill and he was swinging from the aerator (which had been previously out of his reach).
<I see. Digging, at least, is natural: crayfish live in burrows.>
In a nutshell, my question is, is this normal? Should I be worried?
<Depends. If there's anything that might be toxic, like traces of copper (from medications for example) then yes, what you're seeing might be stress behaviours. But if the environment is basically sound, and water quality is good, and the water chemistry isn't acidic or soft, you should be find.>
Also, is there anything else I need to do to care for my crawdad. Various websites I have been to have been fairly vague in terms of assistance. Even the information I'm getting from different Petco people changes from person to person.
<Hmm... does happen.>
Thanks so much!-Concerned 5th grade teacher
<Cheers, Neale; occasional Year 7 teacher.>

ELB Crayfish, comp., fdg., terr. plants...   10/12/09 I recently acquired an almost mature electric blue crayfish. It was identified as a male and will trust in that as I have no way of knowing different. <Hardly matters. They are not animals that get along with each, and are generally one per tank. Sure, you can try and keep two, but eventually one will eat the other.> He is approx. 6-1/2" - 7" long. I have had him for one week, in a 60 Gallon tank at 74F, low KH, med-high GH, ph of 7.0 to 7.3, nitrite and nitrate do not register on my tests. Roommates are 2 small (3-1/2") leopard Botia, 6 mystery snails and, until today, 10 small (2-1/2") comet goldfish. <Well, the snails will be eaten. As for the fish, as soon as he can catch them, he will eat them. Crayfish are NOT suitable for community tanks.> The tank was recently set up, about 4 weeks ago. Goldfish moved to a cooler (non heated) environment. Loosely planted with live plants. <Crayfish are primarily vegetarian, and while they eat meat given the chance, most of their diet is plant material. Needless to say your plants will be viewed as a salad bar. At least some of those plants look like "non aquatic" plants -- and these WILL die underwater. The fern at the far left front is one non-aquatic that will soon die. Take it out. The next two plants at the front might be Anubias, but they might also be Spathiphyllum tasson "Brazilian Swordplants". Again, these are non-aquatics and WILL die. Obviously, dead plants pollute the aquarium. Such plants DO NOT adapt to aquaria and there's no point whatsoever to leaving them in the tank for a nanosecond longer! The other five plants at the front, from the centre to the far right seem to be Amazon Swords, and provided you have bright light and provide them with fertiliser pellets in their roots once a month, can do well. Mostly they just die when bought by inexperienced aquarists because their need for good light and fertiliser is ignored, so be carefully. The thing at the back looks like Water Wisteria (Hygrophila difformis), a species that thrives under bright light. Unfortunately it is edible and will become crayfish food. Do read here: http://www.wetwebmedia.com/FWsubwebindex/keepoutfw.htm If you do have Anubias in your tank, do recall that these plants CANNOT be planted. They will die. Anubias are epiphytes, like Java fern, Java moss, and Bolbitis ferns, and need to be attached to bogwood or lumps of lava rock. Any part of them stuck under the substrate will simply rot, eventually killing the whole plant. If you want to grow live plants, it's absolutely critical to read about each species before you buy them: it's very easy to throw all kinds of money down the drain otherwise.> Stacked slate to hiding spots, etc. Bottom filtration, external filtration. <Undergravel filters are incompatible with plants that have roots in the substrate. Such plants will rarely do well, and most species eventually die. Floating plants and epiphytes are the exceptions, since they don't have roots in the substrate.> So that is the background. Now to my issue...... <Indeed.> I noticed this evening a few, very small (1-2 mm or less) bright gold 'dots' on his carapace. I recognized these as he was scratching or rubbing himself with his feeder claws. There are a couple on the 'head' section, one on the thorax and one larger (3 dots) colony on the tail. <Could be harmless commensal organisms if the gold spots are stuck to the shell; if they're pits on the shell, then that implies the water is too soft and acidic.> Since this is a new set up and he was recently acquired from another fish person with multiple tanks, I am guessing that the gold dots are parasites, but I am not sure what may afflict this type of crustacean. <Many.> I know there are anti parasiticals that are available that are suitable for use in tanks with crustaceans, but have never heard of a fresh water version specifically for their (crustacean) treatment. <Don't bother. Most such "parasites" are relatively harmless, and any medications far more likely to cause harm.> Do you know of such a product...or am I wrong and this is a fungal infection? <Fungus can happen, and looks like patches of off-white thread, likened to cotton wool.> Pics of tank and Crayfish attached, and the gold dots are clearly visible in the second section of the tail, to the right of the thorax (as viewed in pics). Darned things seem to have appeared overnight. (please note that the cloudiness in the tank is from fluorite substrate (specific to the planted areas only) that had not completely cleared from RE-planting the plants that my blue demon crayfish uprooted) Are the 'dots' something that I shouldn't even worry about? <Probably not.> I have kept fish for many years, but have never had this particular incidence. It makes me think of 'gold dust' or velvet in its early stages in fish, but no other species are affected. Any ideas? <Fish parasites -- Ick and Velvet -- won't parasitise crayfish, though their infective stages can of course move from tank to tank via the wetness on the shell of a crayfish just as they can via a wet bucket or wet net. Hope this helps, Neale.>

Question concerning Crayfish. – 06/15/09
Hello there, names Josh. I've been searching the internet for a while now and have yet to come across the information that I am after.
Though your site is quite informative and I've picked up a few bits of info that will help.
<Cool.>
Right so I'll fill you in with a bit of background info first: I've had the tank for about 3 months now, it's a 60 litre (15ish gallons?) tank and my first addition to it was 2 crayfish, which I believe are Red Claw crayfish
but im not 100% on that.
<A bit small for Crayfish and fish; do bear in mind Crayfish are opportunistic, and they'll view small fish as potential food.>
Shortly after I added several fish including some different types of tetras, a couple of bronze corydory's, a Plec (who is growing extremely fast), a male and female fighting fish and recently a couple of guppies.
<None of these are viable in 60 litres. A Plec will need something upwards of 200 litres, Corydoras should be kept in groups of 5+ specimens in tanks 90 litres upwards, and Guppies also need a lot of space, say 90 litres, because the males are very aggressive towards each other and the females. A male Betta is simply Crayfish food, being so slow and easily captured, and in small tanks, male Bettas do tend to harass female Bettas.>
I've lost a few of the tetras and a guppy which im not too bothered about, as when I bought them I expected a few of them to get caught, I guess its good for the crayfish's diet to have some live food available (which has become pretty much impossible to acquire with a lot of new laws coming in in England about live bait....).
<The English laws are about animal cruelty, and sticking animals together and not caring if some of them get eaten is irresponsible, whether or not you personally view it as cruel! These laws don't stop the trade in live
river shrimps, bloodworms and other invertebrates, but yes, most retailers have taken these laws to mean the use of feeder fish is prohibited. It isn't clear that's true in point of fact, though doubtless someone could
make a case and set a precedent. That American hobbyists use feeder fish isn't an advantage; Bob has long argued that feeder fish are a major cause of mortality to things like Lionfish, and recent work on Thiaminase has clearly demonstrated that Goldfish and Minnows are highly inappropriate foods for predatory fish. So unless you're breeding and gut-loading your own livebearers or killifish, there's no safe way to use feeder fish, and moreover, most predatory fish don't need them anyway. Besides, crayfish are largely herbivores/detritivores anyway, so there's no need to give them live fish as food. Algae wafers or their equivalents make excellent staples, augmented with occasional offerings of meaty foods such as small
pieces of krill and lancefish now and again. Do see here:
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
>
The crayfish are around 4-5" now and are about to moult again. Their diet includes sinking pellets named "Crab Cuisine", flakes of fish food that the fish don't get, live plants, and frozen food such as brine shrimp and bloodworm.
<Fine.>
Okay so here's my query: Since I've bought them I've been noticing that they have these strange white worms on them, they are usually around the front of their face, near the eyes and the shorter antennae/feeler things they have.
<Harmless commensals.>
But they do move around the body as well... At first i thought they might be somewhat beneficial to the crayfish cleaning them and stuff but I thought it best to check as when I was searching the internet I came across an un-answered question where someone's crayfish was found dead with "loads of white worm things crawling out of it".
<Not a threat as such.>
Also I was wondering if you could provide me with or point me in the direction a DETAILED list of food (household vegetables and meats) that the crayfish can eat because I don't want to be putting something in there that will be harmful to them.
<See above, and stop feeding them live fish.>
Thanks a bunch for your time and I'm sorry if you've already answered a similar query and I've overlooked it. :)
<Cheers, Neale.>

Crayfish Questions - 05/03/09
Hello crew,
I am going to say about two months ago I came home to find something hiding behind a plant in my tank. I quickly asked my father if he had put anything in there and he said he had put a royal blue “lobster” in there.
<Oh dear... fun as Crayfish are, they aren't really good additions to aquaria with either fish or plants, since they view both as food! Do make sure you read here:
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
It's a great primer to these interesting animals.>
I was ecstatic since I did not know you could keep such a pet and had always wanted to keep a lobster as a pet (in freshwater anyway…I later learned that it is not a true lobster but a crayfish from reading many sites devoted to this type of thing). Anyway, he lives in a 10 gallon tank with 1 beta (which he has attacked the other night), 4 ghost catfish, 1 bright yellow cichlid (which is separated off since he attacked the beta before the arrival of the "lobster"), 2 mollies, and 2 guppies (was three but he ate one of these before I noticed he was in there).
<Way overstocked for 10 gallons! Mollies need much more space than this, and Guppies, well, I'd sooner keep them in 15-20 gallons. I'm assuming the cichlid is Labidochromis, which really has no business being in this system at all, and yes, by community tank standards it is far too aggressive. It's actually a fairly mild Mbuna, and a good one for beginners... but not a community fish.>
I realize this probably is a crowed tank for him but like I said I did not know I was getting one so there was really nothing I could do since the other three tanks in the house were not acceptable homes for them. The five gallon tank was full of goldfish, the 55 gallon is saltwater, and the 75 is freshwater with very large Oscars, Pacus, parrot fish, upside-down catfish, and etc, which would have eaten all of my fish in one swallow.
<Hmm... okay....>
The last water change was two weeks ago and another one is going to happen today. When my father purchased the “lobster” he also purchased Spirulina discs for him which the lady at the store said he would eat.
<Indeed; an ideal food for them, though fresh greens and the odd whole lancefish or unshelled prawn is even better.>
He did eat them but then I learned through my research that they also like other types of food which contain protein.
<Plenty of protein in algae wafers. Turn the bag over and look at the nutritional breakdown; if it's the same as the wafers I'm using, there will be around 25-30% protein in there, far more than these animals would get in the wild. Just as a reminder, Crayfish are largely herbivorous animals that do some scavenging on the side. Mostly they eat algae and organic detritus, but once in a while they'll find a dead fish or something. Their requirements for food are not major, and it's actually calcium and to some degree iodine you need to worry about, not protein.>
So my mother said I should go out and get some of the Pollack from the freezer and give him some of that. So I went out and cut off a tiny piece and gave it to him. He quickly grabbed it up and devoured it.
<I bet!>
The next day I gave him an algae disc and he did not eat it. I figured he was probably just not hungry after eating the fish the day before. So the next day I did the same thing and have been doing so for the last few days. I have not seen him eat an algae disc since his first experience with the fish I gave him, but will eat fish when I drop it in. Is the fish just more filling or should he be eating something different?
<He certainly doesn't need daily feeding.>
What is the ideal diet for him?
<Anything, provided it's varied, rich in calcium, contains fresh greens, and is fed SPARINGLY. Do see the linked article mentioned above.>
Also, I noticed the other day that his tail was red where it is normally white, but when I came home that night he was back to normal so I didn't think any more about it until the next morning when he was redder than the day before and then when I came home that night he was back to normal again. Is this something that should be taken care of or nothing to worry about?
<Difficult to say; assuming water quality is good, the main health issue is iodine, and you want to be adding some to the water, otherwise moulting tends to go wrong. Buy some iodine supplement from your local marine aquarium pet shop, and add at half the quoted dose.>
He does not act like anything is wrong with him. He is very active and attacked one of the fake plants in the tank last night when I went to turn out the light. Any help with these matters would be greatly appreciated.
Thank you,
Dee
<Good luck, Neale.>

Wild crayfish 5/17/08
HI,
I was wondering if it is alright to go and catch a crayfish from my creek and put it in my freshwater aquarium...
<No, unless your creek is in the tropics. Putting a coldwater crayfish into a tropical aquarium is setting yourself up for a disaster one way or another. Likely the crayfish will die, rot, and so decimate your aquarium's water quality.>
with 2 iridescent catfish,
<Danger! Danger! Not suitable for home aquaria. These things can get to 2 m/6' in the wild, and even in aquaria routinely reach 60-90 cm/2-3'.>
Columbian shark,
<Brackish water when young, needs at least 50% seawater salinity once mature. Also a schooling fish, and apt to be very listless and unhappy kept singly. Keep in groups of at least 3 specimens.>
dojo loach,
<Coldwater animal; do not keep above 25 C/77 F.>
brown ghost knife, elephant nose,
<Amazed the Elephantnose is feeding in this system. How long you had it? Most captive specimens die after a few months from starvation. Can't imagine it is getting enough food with loaches and catfish in its tank.>
and an algae eater.
<Gyrinocheilus aymonieri by any chance? Be careful with this. Becomes increasingly aggressive with age. Reaches around 30 cm/12" once grown, and hardly eats any algae once even half grown.>
If it is ok to capture a crayfish and put it in, should I clean it to make sure
it want emit any parasites, or diseases into my tank.
<Don't do it.>
If so what should I use to clean it?... Also, If the crayfish starts to try to pinch my fish, is it okay to put like a rubber band around their claws so they won't, because I'm pretty sure that they don't need them to scavenge for food, only for defending themselves (but I could be wrong).
<No to all of this. Think about how you'd feel if someone tied up your hands all the time, just so you wouldn't make a mess. The key to humane animal care is to understand what an animal *wants* to do, and then create an environment around that. Crayfish are lovely pets, so why not create a small tank (say, 75 l/20 gal) with a sponge filter, some floating plants, and a cave of some kind. Add your crayfish, and let it do its thing. If you have a big tank, you could keep several specimens and try breeding them. Great fun to watch, and the babies are easy to rear. But they are *very* territorial and will fight, eat one another if cramped.>
one last thing, my Columbian shark is currently only about 3 or 4 inches long,
<Already LONG overdue companions of its own species PLUS a brackish water system at not less than SG 1.005. Will become increasingly nervous and restless if you don't do this, and will simply die eventually from Finrot, Fungus or similar. So this isn't a discussion point -- if you want this fish to live, it needs a proper tank suited to brackish water fishkeeping.>
so is it to small to have a crayfish in with it.
<Most crayfish are intolerant of brackish water, so no, this isn't an option. Colombian Sharks are predators anyway, and feed primarily on shrimps and crabs.>
I would appreciate any help you can give me thanks.
<Hope this has helped. You've got some great fish there (in other words, species I personally like to keep!) but they're almost entirely incompatible with one another, so your first job is to separate them into tanks suited to their long term welfare. Cheers, Neale.>

Re: wild crayfish 5/17/08
well, first off my tank is a freshwater tank, not tropic...
<Doesn't matter; your fish are mostly tropical freshwater species that need around 24-26 C, except the Dojo Loach (Misgurnus sp.) which needs cool freshwater, around 15-18 C being about right. The catfish Sciades seemani is only found in tropical freshwater when young, and migrates into estuaries after a few months. Arguably a marine fish once mature, though adults do perfectly well in mid- to high-end brackish water aquaria. Locally caught crayfish will (obviously) need whatever your local climate dictates. If you're in the temperate zone of Europe or North America, then relatively cool conditions; if you live in tropical Africa or Asia, then tropical conditions. Simple as that. You wouldn't expect a penguin to survive in a desert, so why imagine a coldwater fish/invertebrate would be happy in a tropical aquarium?>
the tank size is 500gallons, home made..
<Nice!>
also I feed my elephant nose brine shrimp and it goes crazy for them...
<Brine shrimp aren't acceptable in the long term, and one reason he "likes" them so much is he's starving by inches. Adult brine shrimp contain virtually no nutritional value; feeding fish a diet based on adult brine shrimp is like expecting people to survive on cucumbers. Brine shrimps are primarily a source of fibre as far as fish go, and MUST be used as a treat, not a staple. Baby Brine Shrimp on the other hand are excellent, which is why they're widely used to feed newly hatched fish. But adult brine shrimp are obsolete as far as the hobby goes, and certainly shouldn't be used any more often than once a week. Elephantnoses need things like insect larvae. This is really no big deal as they will happily take (wet) frozen bloodworms and the like, which will work out cheaper than live brine shrimp anyway. Do read Bob's excellent article on these fish, here:
http://www.wetwebmedia.com/FWSubWebIndex/mormyrids.htm
The vast majority of Elephantnoses die prematurely because they starve to death across a few months. Big mormyrids like Gnathonemus petersi should easily live 10+ years, but people insist on keeping them the wrong way, despite aquarists like Bob and I writing in the magazines explaining their special needs. It's a shame really, because they're lovely fish and fascinating to watch. Widely kept in research labs, which is where I became familiar with them. We'd set up the oscilloscope to detect the electric pulses, so you could "hear" them communicating with one another. Very cool.>
and I will be transitioning my Columbian shark to a full saltwater tank, as he gets bigger, and I will be doing it slowly with separate tanks.
<No need to do it slowly. Just go ahead and do it now. Sciades seemani can be acclimated to saltwater conditions across an hour or two, certainly once around 10 cm/4" long. And please do get him at least two friends; not doing so is very, very mean and won't do anything for your karma. Cheers, Neale.>

Crayfish...     01/13/2008
do crayfishes need land? Also, do you have a good caresheet for crayfishes? I couldn't find any on your site. Thank you.
<http://wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm
and the linked files below. B>

My new pet Crayfish    11/27/06
Hello. I work at PetSmart, and every now and then, strange animals will  show up in the shipments of feeder fish,
<Ah, yes... always a delight, adventure>
and I usually enjoy taking one or two  
home with me. Usually the stow aways are tadpoles, but yesterday, I picked up a Crayfish that I named Garth.
<"He's got friends in lowww places....">
Right now, he is living in a tiny little bowl, but  after reading up on your page and others, I am ready to purchase and set up a  tank for him tomorrow.
<Ah, good>
I was wondering a few things, and if they are on your  page and I missed them, I apologize for the inconvenience.
1. Do you have any idea what he may be? I was trying to find pictures of several species, but after reading up on them, I think he may be a juvenile. He is probably 2 inches long, and he is a light tan color, but he has speckles all  over him, including his pinchers. They themselves are very small and thin, but  they are long. I live in Colorado, but our fish are usually shipped from Arizona. Any species around that area that he may be?
<There are some 300 plus species that occur in N. America, but the vast majority of those seen/used (for consumption as well as ornament) are Procambarus clarkii>
I was just wondering, because I wanted to know about how big he would get.
<Do place the above name in your search tool... likely some 3-4 inch body length maximum>
2. Exactly what/when should he be fed? I have read different things.  Some say stick to mainly vegetables, and don't feed too often, while others say  feed mainly meats, and feed frequently. What would be a good feeding/diet  schedule?
<A mix of these... animal and vegetable foods... prepared or fresh will serve you both well here>
3. How much space should he have?
<A ten gallon system would be perfect... with some rock work...>
I do not have the room for anything HUGE, as I already have a ten gallon fish tank and a large critter keeper for my hermit crab. Would a large Critter Keeper (15.875" x 8.375" x 12.083" )  be enough?
<Yes>
I know some aquatic animals don't need a lot of room, and some  do.
<You are correct here>
Thank you so much for your help. I apologize again if I've asked anything that was available on your web site. Sometimes Im not the best at searching for information, lol. Thank you for your help.
~Amber
<Thank you for writing, sharing. Your genuine concern and intelligence are refreshing, obvious. Bob Fenner>

Forceps Crayfish? - 10/21/2006
Hello There!
<Hello, fellow invert-lover!>
Not long ago my area suffered a week-long power outage, and unfortunately all my fish, Freshwater and Saltwater, have passed away.
<Oh, dear.  I am sorry to hear this.>
I'm currently working on getting my Marine tank up and running again (and when that happens I'll try and get those predatory snails I asked about earlier).
<Neat!>
As of now, however, I have finished cleaning and reworking my freshwater tank, so now it is functioning. It's just empty. One thing that has caught my eye was a species called a "Forceps Crayfish". Its URL is http://crayfishshop.com/product_info.php?cPath=23&products_id=30 .
<Neat!>
I did send for some information on this species, but it's always nice to have another viewpoint.
<Wish I had one for you.  I can't find much at all about this fellow.>
He does seem very interesting and is something that I would like to own, but there seems to be very little information about him. My biggest worry is his maximum adult size. If he gets as large as those "Giant Australian Lobsters" then the Forceps Crayfish will be totally out of the question. If his size is on par with the classic "blue lobsters" then he will much more manageable. As far as I know, there really is no species of crayfish that is particularly delicate and sensitive. Please correct me if am wrong.
<Correct, for the most part.  I really don't have any clue how big this fellow will grow.  If they're shipping 6" individuals, though, I imagine they will exceed that size by a good amount.>
p.s. I have NO intention of keeping any other animal in the tank with the crayfish. The aquarium will be a display tank meant to house him and only him. Any compatibility issues will be irrelevant.
<Perfect!>
Thank you VERY much.
<I only wish I had more to say.  Do please let us know of your experience with this animal, should you choose to go forward with it.  Wishing you and your future Cray well,  -Sabrina>

Australian blue crayfish breeding question   9/16/06
   Hi, I currently have a 125 gallon tank with 15 gold/blue/moonlight gouramis, 4 rainbows,1 big pleco, 3 Bala sharks, 2 tinfoil barbs, 1 four line catfish, 1 clown loach, 1 black ghost knife, 1 ornate Bichir and a 5 inch Australian blue crayfish.
<Hope this last isn't hungry...>
The Crayfish has been in the tank since i started about 6 months ago and have added the fish slowly over that time.  
Other than the occasional disappearance of new fish
<...>
everything seems to be in harmony and has been for a few months.  The 5 inch female crayfish is in my 125 gallon tank and i have recently bought a 2 inch male aussy that is currently in my 38 gallon tank.  I have the hopes of one day having them breed.
<Can be done>
  I know these species get very large and I am assuming I have a large enough tank to give both enough space.  It also has lots of driftwood, ships, tubes, tunnels etc.  The 2 main threats to the small crayfish I imagine are the Bichir and the big crayfish.
<Not the Bichir unless it's really much larger>
Also just a note that the big crayfish is very well fed lettuce, carrots, peas, algae wafers, shrimp, bloodworms, brine shrimp) and any fish can come near her without much fear, she will just raise her claws and shoo them away.  She is very active but not overly threatening.  So my questions are as follows.  Will the small crayfish grow fast enough to get close to matching the other one in size?
<I'd wait till they're closer... and introduce with a barrier twixt for a few weeks... and then release only when you can be present to "supervise", re-separate if necessary>
how long might it take?
<Likely a few months>
If I relocate the Bichir will it be possible for the 2 to get along considering the amount of space and hiding places?  Any suggestions?  Also, last question for curiosity sake.  How long can an Australian blue crayfish live?
    Thanks so much, Chad
<Please read here: http://www.wetwebmedia.com/FWSubWebIndex/crayfishreprofaq.htm
and the linked files above. Bob Fenner>

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

Australian blue... read   7/18/06
hi; we have become the owners of a creature advertised as an Australian
<Grammar...>
blue lobster after our daughter fell in love with it, after some research I believe it to be a crayfish and it seems to be happy living in its own new tank. I am an experienced fish keeper but know hardly anything about these creatures. it is a very lovely looking thing however the aquarium shop we had it from advised us on the food it needed and told us to feed it 1 pellet 2xday. the poor thing looks like it is always searching for food and I would love some advice as how to know how much to feed it. also the shop couldn't tell us the sex of it and I believe it is to do with the segments on its tail. can you help.
many thanks dawn-England
<... Dawn... what happened to your English? Please read here: http://wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm
and the linked files above. Bob Fenner, who needs to fix your writing now...>

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

Mixing Crayfish And Bichirs  4/09/06
Hi, thx in advance for answering my question. I have a 40 gallon tank with (1) 4 ½” Australian blue crayfish, (2) gold gouramis, (2) pearl gouramis, (1) Bala shark, (1) pleco.  I would like to make a Bichir the final addition to my tank, but of obvious reasons there may be a clash between my crayfish and the Bichir.  Do you have any thoughts on how this setup will work? Sincerely Chad
< The crayfish will try to eat the Bichir at first depending on the size of each. As the Bichir gets bigger there will come a time when the crayfish will molt and the soft new shell will leave the crayfish vulnerable to attack by the Bichir.-Chuck>

Keeping Crayfish - 03/13/2006
My son just found a crawdad in a creek behind our house and was wanting to keep it as a pet to which I don't have a problem with.  
<Can be done, with a bit of studying.>
Here's the thing, I have read most of the articles from other people but I am just lost.  Is one from the creek just like the ones they buy at the pet store or is there a difference in how a tank should be set up for one.
<Actually, in the US, the most common crayfish offered for sale in fish stores is Procambarus clarkii, almost certainly the same animal as your son found in the creek.>
I would just go to a pet store around here and just ask them and get everything while I was there, but the last time I did that I ended up with a lot of stuff that wasn't needed for the pet we had.  I would love to keep this crawdad as a great experience for my 12 yr. old. Any help would be great.  What size tank,
<Depends entirely upon the size of the animal.  If this guy is more than a few inches in length, I would advise to put the feller back in the creek, and go looking for a smaller Cray.  If he's a few inches or less, a 20 gallon tank would be great.  Be CERTAIN to have a good, tight fitting lid.>
how much water,
<Tank should be mostly full, and have a tight fitting lid.>
water temp,
<Room temperature will be okay - try not to let him get too warm.  No heater.  Tight fitting lid.>
and lighting,
<A fluorescent aquarium light will be great.  Don't use an incandescent light; this will raise the temperature of the water dangerously.  Very often, you can get light/lid combos.  Did I mention a tight fitting lid will serve you well.>
I understand the rocks and cave things.  
<Lots of hiding spaces will be necessary.>
Also what is the ph y'all are talking about?   
<A matter of water chemistry....  Please read in the freshwater articles of WetWebMedia regarding water quality and maintenance.>
Again thank you for the help.  Dena
<All the best to you,  -Sabrina>  

Novice has question about crayfish   3/3/06
Dear Mr. Fenner:
<Karen>
My 10-year old son brought home a crayfish from school to care for over the summer.
<Ahh, I had these (Procambarus clarkii and others) at this age as well>
We became attached to it and have kept it ever since.  We  don't know what species it is, but it started out red and has now turned  blue.  The
school provided a very small plastic "tank" with a few pebbles  (no gravel or sand).  We kept it there, but after a few moltings it had  grown pretty large
(about 5 inches), so we moved it to a 10-gallon tank that we  just set up.  We have gravel on the bottom, some pebbles, some plastic  plants, places for it to
hide, a filter, and an aerator.  We know  nothing about crayfish, but we have been reading up on the Internet (and now  realize that it should have had more
space and a more varied environment long  ago).  My most pressing question (I'm sure we'll have more) right now is  this:  ever since we brought it home,
we have been feeding it "crab and  lobster bites" (by HBH), which the pet provision store said would be  appropriate for crayfish.  It seems to have been
doing well on these.
<Yes... a good company... with real science...>
  We moved it to the larger tank yesterday, and we gave it the same crab and  lobster bites.  We have noticed that it has been eating some of the  gravel.  Will this harm it?
<No, not harmful>
Is it doing this because in its previous small tank, there was a smooth bottom with no gravel, no sand, and  only a few pebbles, and now the gravel in the new tank is confusing  it so that it is having a hard time distinguishing gravel from  food?  If this is a problem, do you have any suggestions?  
<Not a worry... just part of natural behavioral repertoire>
Thank you very much,
Karen
<Welcome. Bob Fenner>

Differences between lobsters/crayfish/species....?   1/26/06
I recently purchased an "electric blue lobster" from a trusted pet store, but when I search the internet for
information, I find many different names/species/varieties.
<Yes... you start to understand the value in scientific names... many organisms have more than one common moniker, and these are often applied to more than one species>
I called the pet store to see if they knew the Latin name
of the species they sold me, but to no avail.  I have searched for hours for a way of determining what it is that I have
actually purchased.  Could you enlighten me as to what the physical differences are between lobsters versus crayfish,
species of crayfish,
and how to identify what variation I have?
<Can... a beginning... both common names are applied to a few groups of crustaceans... marine and fresh... that is, the terms crayfish and lobster are often used for different taxonomic groups... They are not definitive as to their systematic classification>
I also wanted to commend you on the fantastic website you have here.  I am extremely impressed (almost a little
overwhelmed) by the enormous amount of information you supply.  Thank you!!
Tammy
<A photograph will be useful here. Have you read through the freshwater and marine articles on crayfish and lobsters posted on WWM? There are some pix, systematic information, identifications there. Bob Fenner>