Crayfish basics, hlth., env.  – 11/12/09
Hi.
<Hello there>
My son has 5 small crayfish (2"-3") in a 75 gallon tank. They all seem to get along OK, no major fights and only occasional skirmishes. However, they have all developed a condition where they seem to have white feathery things growing out of their sides and white fuzz around their faces.
<Mmmm>
The white feathery bits seem to have a bit of red in them, at the ends. I would like to send a picture, but I don't have an appropriate camera.
<Drat!>
I found on your site that this is apparently caused by a poorly executed molt, caused by poor nutrition and poor water conditions. That was all I could find.
<This is one principal "cause" here... but indirect. That is, what is it that lead to the poor moult is the real concern. Do you dose "iodine"? Have sufficient biomineral (Ca, Mg mostly) and alkalinity content in your system water?>
We *were* overfeeding them on protein, as the article described.
Now I have a few more questions:
1) What exactly is that stuff? Is it a fungus or what?
<Can't tell; but could be>
2) How do I get rid of it?
<Better conditions>
3) Does it hurt the crayfish just by being there?
<Too likely so>
4) What exactly are the ideal water conditions for crayfish?
<Posted: http://wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
and the linked files at the bottom>
5) Since they all have it, is it contagious?
<Mmm, yes; but in this case, the cause/s are communal, not so much that the vector is contagious>
I have never kept fish before. My husband fancies himself something of an expert, but knows less than nothing about crayfish.
<Heeee! Ah, the human condition>
Please help. My son loves his crayfish. I would hate to see them all go belly up.
Thanks.
Erin
<Do read a bit more and write back if a path has not awakened to your  conscious. Bob Fenner>
P.S. I really appreciate what you are saying about well-written letters.
It is appalling what some people will consider as communication, even in printed matter. People do not realize what a difference it makes when you are clear about what you say.

Re: Crayfish basics  11/13/09
Ok, Bob,
<Erin>
I looked over your site until my eyes are ready to bleed, and I did find a little more info. Now I know to buy algae pellets and only occasionally give a shrimp pellet for a treat. Is Once a week appropriate?
<Two, three times per week is ideal>
We also noticed that they love corn, peas, and edemame beans. Is this ok to feed them, too?
<Sparingly, yes>
I also know to give them iodine and to change the water 25% a week.
<Yes!>
What I don't find that I wanted to know is, when I stick a test strip into the tank, what is it supposed to say?
<Mmm, I really don't like test strips... sorry. They're notoriously inaccurate and imprecise... not measuring right or consistently what is there>
I found contradicting information about pH levels, and no actual acceptable ranges for nitrates, nitrites,
ammonia, or whatever.
<Most Crayfish species like water that is neutral (7 ish) to moderately alkaline. Low Nitrate (under 10 ppm), and NO ammonia or nitrite period>
I found only passing references to these things. So specifically, what am I testing for, and what numbers do I want?
And another question about water. My husband brings home City of Chicago tap water from his work. It has a lot of chlorine in it, but that is what we use for the tank. He swears you can just let it sit in the bottles with the tops off for a while to let the chlorine evaporate,
<Likely so... but nowadays it is very likely treated with chloramines, not chlorine... Need to leave the tops off for a week or so ahead of use>
but I am not so sure. The pet shop guy tried to sell me something to treat the water with, but hubby told me not to buy it. We have nasty rusty well water at home.
I use a salt water softener for household water,
<Mmm, likely a salt-recharged type. Don't use this water>
but we drink the city water.
Can we use the softened water, or is the city water better?
<The city>
Thanks again for your help.
Erin
<Certainly welcome. BobF>

Re: Crayfish basics  11/16/09
Hey Bob!
Thank you so much for all the helpful information. Sorry to be a bother, but I wanted to ask you, what are the ideal Ca and Mg concentrations for the water?
<Doesn't matter the exact values, but something on the "medium hard" to "hard" scale of whatever test kits you use should work just fine. While pH should be in the basic range (7.5 is ideal) the hardness is critical too.
Generally, if you have water that furs up kettles quickly, you should be fine. But to be on the safe side, adding Rift Valley salt mix at about one-half the amount of stated for Malawi cichlids will do just fine. Cheap, easy, and effective.
http://www.wetwebmedia.com/FWsubwebindex/fwh2oquality.htm
>
I missed that the first time I read your original reply. And, some good news--the pet store sold us an anti-fungal for the crayfish, and apparently it is working because the "feathers" seem to be dropping off and the
face-fuzz seems to be going away.
<Cool.>
I know we have to take better care of the water, but it is a relief to see them feeling better, anyway!
Thanks again!
Erin
<Happy to help. Cheers, Neale.>

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.>

Nitrate concentration in crayfish tank – 06/28/08 Hi,= I have a problem with the nitrate level in my crayfish tank which I hope you can help with. It's only a small tank, just under 10 gallons, with an undergravel filter and another small internal foam- filter. It has been set up for over three months, and my crayfish (the only occupant) has been in it for two weeks- less than that. Since I added her, my nitrite and nitrate readings have always been 0. For the last couple of weeks, my nitrate level has jumped to 25 mg/L (nitrite still 0) and I cannot get it down. I know this is not high for fish, but am concerned that it may be too high for her as a crustacean. I have always done 25% water changes each week. The last couple of weeks, I did two 10% changes the first week, and then, as the nitrate level didn't decrease, a 50% change about 5 days ago. It doesn't seem to have any effect. I tested the nitrates of the tap water, after conditioning, and this was 0. I suspect its the amount of food that she loses when feeding (miniscule bits of fish seem to 'cloud' off while she chomps) and I do have some brown scum/algae which accumulates at the front, which I keep having to scrub off. I can't understand why the water changes are having no effect. I don't know whether doing any more just yet is a good idea as I don't want to start the tank off cycling again. Have you any suggestions? Should I be worried about this concentration? Thanks very much for your time. I couldn't find anyone else with this query for crayfish tanks. Best wishes, Kathryn <Hi Kathryn. Nitrate can be difficult to manage. The first thing is to establish the nitrate level in your tap water, which you have done. If you're finding that the tap water has 0 mg/l nitrate but the aquarium has 25 mg/l after one week, you almost certainly have an overstocked or overfed aquarium. Given that nitrite and ammonia are zero, the filter itself is doing its job just fine. Your crayfish isn't in any immediate danger -- the common swamp-dwelling crayfish sold as pets have evolved to live in a variety of water conditions, and will adapt to relatively high levels of nitrate without problems. Given the crayfish are primarily herbivores in the wild, you could opt to focus the diet on plant matter. There is less protein in plant material, and while your crayfish will still receive all the nutrition it needs, the amount of ammonia dumped in the water, and consequently the nitrate produced by the filter, will be far less. Across the week you might feed your pet on 5 days with plant material, and 2 days with something meaty. Beyond that, more frequent water changes will dilute the nitrate, and the use of fast-growing floating plants under bright illumination will further use up nitrate. Hope this helps, Neale.> Re: Nitrate concentration in crayfish tank – 06/29/08 Hi, Thank you very much for your advice- I will certainly try to shift her to a more vegetarian diet and find some floating plants. Hopefully she won't be able to catch and destroy them like she does everything else! Thanks for your time, Kathryn <Glad to help. Try soft plant foods like tinned peas and cooked rice as staples. The peas are great for protein, and the rice provides starch. You can also offer Sushi Nori, cucumber, courgette (zucchini), cooked carrot, blanched lettuce or pretty much anything soft and/or green. There's no need to feed crayfish every day. Feed in small amounts, and at night if you want to minimise wastage (crayfish are nocturnal). Inexpensive pond plants like Elodea will do double duty as forage for the crayfish as well as nice decorations for the tank. Maybe once a week offer something meaty with either shell or bones in place. These provide the calcium required for successful moults. Frozen krill and/or lancefish (both available in aquarium stores) will do the trick here. Some aquarists recommend adding iodine drops to the crayfish aquarium. You can buy this stuff (inexpensively) at marine aquarium stores. It seems to help prevent one common problem with crayfish, namely "bad" moults, where the crayfish dies part-way through. Use as indicated on the bottle, though perhaps a half-dose would be ample for just one crayfish. Cheers, Neale.>

Crayfish, sys.  – 10/09/07
I have a freshwater tank with a red crayfish in it. Some of the readings I read said to add iodine. I was just wondering if the iodine could harm the freshwater tank and could it harm the cichlids that I have in it now. I was also wondering what brand of iodine I should get for my freshwater. Thank you very much for your answers.
<Should be fine if used as per Sabrina's instructions here: http://www.wetwebmedia.com/FWSubWebIndex/crayfishfaqs.htm . But just to be sure, start with a low dose (maybe 50%) and observe. If the fish start behaving oddly, do a water change and use a lower dose. It goes without saying that crayfish and fish shouldn't be kept in the same tank anyway. Cheers, Neale>

Yabbies and algae control   5/23/07
hi,
<Howdy>
I read through alot of Q&A but didn't find my specific question. I apologise if I missed it.
<Okay>
I have two small yabbies (around 2 inches) as well as some smaller feeder fish which am happy to say have not been eaten. My problem is I'm gettin algae building up in the tank. Is there any kind of algae eater that would survive with them.
<Mmm, maybe...>
Are they just as likely to attack fish on the glass as fish swimming through the water? Or are snails a possibility to slow down the amount I need to clean the glass?
<The snails are a poorer choice... too slow... I would actually try a Chinese Algae Eater (Gyrinocheilus) here. And read re other algal control strategies... here: http://www.wetwebmedia.com/FWSubWebIndex/fwalgcontrol.htm
and the linked files above. Bob Fenner>
Regards,
Matt

Questions GALORE! Crayfish sys., Salamander nutr., ADF nutr., Neon Health,   1/19/07
Wow. The forum rocks. I kept trying to find the sites with information and realized all the questions I could have were pre-archived before my very eyes.
But, despite other's curiosities, mine persists.
Here goes a big thank you to the crew once this message gets drawn and quartered to the appropriate experts.
<About a day>
Crayfish:
Recently, I caught four 1 inch crayfish from a quiet Atlanta stream (other beauties accompanying below).
As I read, I did my research and studied their natural home (a stone's throw away) extensively.  Although their water is quite cold now (being an icy Ga. Winter), I attempted to recreate their environment in a 10 gallon tank. I provided a good number of rocks (atop gravel bottom) for them to hide.  These rocks, I made sure, came with natural moss/algae from their stream and they have all taken to the four corners and pretty much kept to themselves. I think I did an ok job, as they all remain quite hidden (onlookers other than myself exclaim my tank is empty they hide so well).
Here comes the kicker. There were loads of these crayfish AND Salamanders.
<And plenty for the Crays to eat otherwise...>
I researched the crayfish will eventually pick on anything their pincers can catch.
<Pretty much, yes>
For now, the crayfish are but a fraction of the salamanders' size, but I want to know how I can further ensure they remain comfortable and well fed (feed them wafers, dropping pellets, and elodea or natural moss?) so they won't pester the salamanders but for territorial gain?
<A matter of time, your careful observation>
Other than that, I wanted to know how else to make them comfortable.
There is only about 3 gallons of water at the moment as I tried to recreate their shallow stream - put in aeration and cascading filter. So I'm pleased with the water flow, hiding places, native terrain and roommates - what else?
<Please read here: http://wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm
and the linked files at the bottom>

Question regarding Yabbies and tank size.    1/10/07
Hi. I've been furiously reading your website and am thoroughly impressed at the information you have.
<Like your use of adverbs>
Just thought I'd ask for a bit of advice regarding our Yabbies (hope you don't mind).
<Not at all>
After losing our two original pet shop bought Yabbies fairly quickly to some disease that I'm sure came from the pet shop with them (the pet shop denied this but I noticed they stopped selling Yabbies altogether shortly after my purchase) we decided to catch our own from a local water hole (we live in NSW Australia... and catch our native Cherax destructor). We ended up with one female Yabby (Marge) who has lived with us happily for over a year.
<Good>
Last weekend, after an encounter with a 2 year old (of the human variety), we had to get her a new tank. Which we have done but it is quite a bit larger than her last. It is 2 foot long, 1 foot wide and deep (I think.. used to metric here). So we decided that she might enjoy some company at last.
<Mmm>
Today we went yabbying again and came home with a mix of males and females to put in with her.
<A mix?>
They are not large (smallest female over 2 1/2 inches... largest is a male not quite 4 inches)  however now I am worried we are overcrowding them.
<If the dimensions are what you state, you are correct>
The tank now contains 3 females and 2 males. I think it holds about 56 litres (15 gallons??), however we only have it a little over half full so that they can climb out of the water onto the rocks if they choose to. I have plenty of hiding places for them to get away from each other. Do you think I should get another tank and pull a couple out?
<Yes, I would... and even then... you need to keep an eye on all for signs of overt aggression... particularly during molts>
It is a bit hard at this stage to tell how they are getting along as the only one who isn't frightened of us is Marge. And while she doesn't mind us and will come to the side of the tank when she sees us, she is hiding as well... wary of the new arrivals in her tank I assume.
<I sense you are correct here>
As an aside, and not a question at all, it has finally dawned on me just how badly in drought we are. The water hole we went to today was probably an 1/8th of the size it was at the same time last year. All of the smaller holes around it are gone.  I don't know what happens to the Yabbies when that happens.
<Mmm, hopefully some "walk out" to somewhere propitious, survive>
I guess they just get awfully crowded and become much easier pickings for predators. Sad though.
Many thanks for taking the time to read this.
Kind regards
Tascha Marshall
NSW Australia
<Thank you for sharing. Bob Fenner>

Re: Question regarding Yabbies and tank size.  1/10/07
Dear Bob
<Yes Tascha>
Thank you for your quick reply. The information is much appreciated. We will endeavour to get another tank today to move a couple of the Yabbies into.
Thanks again.
Kind regards
Tascha Marshall
<Ah, outstanding. Thank you for this follow-up news. Bob Fenner>

Re: Question regarding Yabbies and tank size   1/12/06
Hi again Bob.
<And to you Tascha>
Sorry to be bothering you again so soon. Some more Yabby questions.
All seemed  well with our over crowded Yabby tank this morning so we left it as it was this morning while we went to town to get another tank. However when we returned, (with a new tank), we found our Marge with her two front claws missing. The claws of course are no where to be seen, so I'm assuming they've been eaten.
<Yes>
So we moved her into the new tank, along with the smaller of the males. I've been watching both carefully to make sure that she was ok and that he wasn't aggressive towards her.
<Keep them fed...>
Keeping in mind I've never observed two Yabbies together before, but the male (who my children had to name Homer) seems quite fond of Marge. And she doesn't seem to mind him either. Spending a large part of this evening with her tail in his face. If this means anything at all I have no idea. But he doesn't respond to her aggressively so I figure it can only be a good sign.
When they were not sitting around cleaning themselves they were quite active, especially the male. I'm guessing this means they are very pleased to be where they are now.
<Perhaps so>
Now to my question. I have no idea when Marge is due to moult again, but is it likely that she will grow her claws back in just one moult?
<Mmm, not if this specimen is quite large... or your water deficient in biomineral and alkalinity... nor if there has been a history of little nutrient uptake... Likely two, three molts to full regeneration>
Also I have been wondering, is it possible for them to mate with Marge having no front claws? Not that I'm particularly bothered if they mate. I'm just curious more than anything.
<Mmm, not as far as I know... it is the female who moves the "sperm packet", manipulates the fertilized eggs... with her claws... Are both sets (the larger and smaller gone?>
I'm happy so long Marge is going to be ok. Which I assume she will be if she doesn't encounter any more problems. She is eating and moving about as usual, although her favourite pass-time of shifting gravel and hiding rocks will probably be a bit harder for her.
<Yes>
The new tank has a light which has turned out to be a great thing. It is a miracle my family got fed tonight given how much time I have spent sitting in front of the tank watching Marge and Homer interact.
<Good for them to have lessons in self-sufficiency...>
Thanks again for reading these emails. Your advice is fantastic. I'm sure my husband wasn't convinced we needed the second tank until he read your reply.
What a shame you're not available for non-fishy advice. Ha ha.
<I know little about other aspects, avenues of life>
Oh.. before I leave you in peace.... my husband insisted on putting sand and a piece of bark from the water hole, into our larger tank. The tank has not cleared since he did it, despite rinsing both sand and bark well, and use of the filter. I'd rather get rid of the bark and maybe the sand (if the removal of the bark alone doesn't clear the tank) but more importantly I'd like to know if either are likely to cause any health problems for the Yabbies. My husband says the bark feels like rubber and has been in water so long it can't possibly do any damage. But I'm not so sure. Any ideas?
<Mmm, I would "test" this/these materials with a small fish... or two... perhaps comet goldfish... to assure that they are non-toxic... in a separate aquarium/container... for a few weeks. Too likely to haul in undesirable hitchhikers, chemicals...>
Many thanks again and I promise I'll stop bugging you soon.
Kind regards
Tascha Marshall
NSW Australia
<Not a bother. Cheers, Bob Fenner>

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>

Crayfish Climbing - 07/25/2006
Me again with a rather odd problem,
<Hi again!>
Vladimir, (Freshwater Crayfish) Has been trying to climb out of his tank.
<.... and this is odd.... how?  ....This is actually a very normal action, to be expected of Crays....  especially wild-caught Crays or ones that might prefer more space.>
He will only do this in the middle of the night.  We have 2 air driven corner filters for them.  We do full water changes about every week, and try to keep the water as clean and clear as possible, yet he still tries to climb out.
<Really, this is to be expected.>
Would it be possible that Mavra (A female in the same tank as him but separated with a clear divider) is causing him to want to get to her, even if it means climbing out.
<This is in fact possible.>
We had a few close calls with him, he would constantly climb up the air tubing for the filters and almost completely out of the tank (15 gal)
<A little on the small side for space for having only a small section (even if half) of the tank - I'd be climbing, too.  This is a sufficiently sized tank to maintain their health, but they'd do a bit better in a larger system.  Even that, though, may not put an end to the climbing.>
We had to place a barrier over the top during the night to keep him from getting out and falling onto the ground.  
<A VERY necessary component of a crayfish aquarium.>
On a better side, Mavra has molted and is closer in size to Vladimir, but at the same time Vladimir might be getting ready to molt also. I think this might make the gap slightly larger again. The other thing is, Vladimir is a lot more "thick" than Mavra, his body seems to be quite larger in mass than hers. She seems to be about 2/3 the thickness of him and I am afraid this would cause her to be damaged.
<Yeah, I'd give 'em a bit more time.>
Thanks for your time,  -Colin
<And thank you for your emails, Colin!  I hope you will some day see baby crayfish from this pair!  All the best to you, Vladimir, and Mavra,  -Sabrina>

Crayfish In A FW Tank  - 04/27/06
Hello, I contacted you the other day about my 55gal setup and had a few more questions to ask. My blue crayfish hasn't bother any other fish yet unless they actually come into his cave. He doesn't seem to be worried about any of the other fish as he will even sometimes roam around during the day and I make sure he gets fed. Sometimes my shrimp are in the cave with him filtering the water and he usually doesn't mind them. He is slightly bigger then them but he is only about an 1 3/4in. Will he become more aggressive as he gets bigger?
<He will always try to catch something to eat. Just because he can't catch them now doesn't mean he will give up trying.>
I am assuming being a crustacean he molts as he grows and was wondering if you need something to add calcium or iodine to aid in the molting or if he will do fine alone.
< Usually the minerals in the water are enough. Sometimes iodine needs to be added but this all depends on diet and water chemistry.>
I don't use a reverse osmosis filter and I use freshwater salt at the recommended 1 tbls per 5 gal of water.   Also, he has a habit of eating the roots of my smaller plants. He eats my algae wafers but still goes after my plants. Would something thing like lettuce or zucchini help?
< Try it. Lettuce has very little nutritional value.>
I was also curious of my disc and my silver tipped cat stretching their mouth and fins every now and then. Could this be a problem down the road or have something to due with water quality?
< This is a way that fish realign their jaws. It could be more of a result of the food then a problem.>
   I am appreciate your help very much since the locals don't seem to know much except how to sell them.  Even other resources on the web either don't answer or take over a month to reply.   Thanx again for your time. :-)    Jason  
< The WWM crew are all aquarists and know how important time is when you need a reply. We are all volunteers and try to get to as many questions as we can. Thanks for the kind words.-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>

Crayfish
I was wondering wither I could successfully keep a crayfish in a 2.5gallon tank with a sponge filter.
<it would be a little cramped, but it would likely work too. They are incredibly hardy creatures.>

Cherax sp. with a Doritos Diet?
Hello there!
<Hello! Ryan Bowen with you today.>
I'm Tracy, nice to meet you!  *waves*
<Ah, nice to meet you as well>
We just got a pet crayfish recently cause the people at my mom's office got tired of taking care of it.. =( <Too common, sad>  But we're doing our best to take care of her now. <A fishkeeper is born>. I learnt much about how to do that from your site, so many thanks!  And I identified her gender, which no one bothered to do in the 1 year they had her!!  *rolls eyes* <Nice work!>
Anyway, she was very active for a few days and climbed all over the tank exploring.. or whatever it is crayfish do.. but we're quite concerned now cause for the past few days she's been hiding in her hole most of the time and staying very still for long periods of time.  Even at night, she only gets out to climb around for a bit, then she's back to hiding.  At first we thought she might be molting, but nothing has happened for 5 days.  Does preparing for molting take that long? <It can, and after the animal molts it will remain hidden as the shell is not hard yet.>  Or is there another reason for her behaviour?  We try to keep the tank clean.. uneaten food is taken out after a few hours.  About 20% water change every week.  We feed her sinking fish food and bits of peeled tomato.  There's limestone in her tank.  I am not sure where I can find iodine in my area, does feeding her fish/prawns occasionally work as well?  <Water changes alone should be plenty of trace elements.>
Shy says hi!  I'm not sure what species she is.. she's blue all over though! <Cherax sp.> The brown markings are actually algae cause her previous owners fed her potato chips and didn't clean her tank enough. *grumble* <I'm not surprised that your pet is "adjusting" to her new environment!> She's about one year old and is 5 inches long. <That's about as large as she'll get.  Feed sinking algae pellets, and supplement with some small, meaty items for best coloration.> And very adorable!
Thank you for bearing with me, I can get really long-winded at times.. =)
<No worries!  You ought to hear how long those "reef" guys get.. sheesh!  ;)  Ciao Tracy!>
*hugz*
Tracy

Yabbies, Pet Crawfish?
Hello -
I am a huge fan of crawfish, Yabbies as I have heard them referred to. However, I prefer them steeped in a spicy stock and served up with potatoes, corn, and sausage. (Sorry to all those who disagree) Here's my question....my son (he's 11) usually helps me when I cook outside (BBQ, fish fry, crab boils, etc.) This weekend we had a crawfish boil and he managed to keep a few hidden from me. Now he would like to keep them as pets. he has a tank with platies, and a swordtail. I am certain the crawfish would eat them as soon as he could get his claws on them! So tell me, PLEASE, what could I do or should I do to keep them in captivity and keep them alive? He has 3 of them about 3 inches in length each.
<I have kept crawdads for years as a kid and never really had any problems with them. One per tank is best because they will just fight with one another. They are scavengers and will eat anything including the other fish you mentioned. The are messy to and will require a good filter and lots of water changes to keep the water clean and to help reduce algae.>
I currently have an African Cichlid tank with lots of rocks. It's a 35 gallon tank and has 15 Cichlids about 2.5 - 3 inches each. Would they be compatible with them? I know the Cichlids are aggressive, and so are the crawfish! Who would eat who?
< The African cichlids would be too fast for the crawfish to catch them. In the wild they live with large crabs so they know their way around. When the crawdad sheds its exoskeleton it will become a living breathing mobile banquet block and be eaten by the cichlids and never seen again.>
What do you recommend? What kind of water conditions do they prefer? What kind of filtration is necessary? What size of tank is needed? What types of substrate is best?
What kind of set up is needed? I would like to get away as cheaply as possible. These crawfish were not bought at a pet store, so I don't think they were bred to be kept as pets. My guess is they won't live for too long, but I don't want to break my sons heart. I would like to put forth some effort to keep them for him. (By the way, I had to get him a happy meal while we ate today!) Thanks so much for all your help!
< Get one of those 10 gallon starter kits that you see at the fish store all the time. You don't need the heater though. Place about one inch of inch of washed sand on the bottom and somewhere for him to him. Watch for chlorine in the water and copper from any new plumbing. They will any type of sinking pellets. Just make sure to not overfeed and pollute the tank. He will need to change a couple of gallons of water every week until the bacteria get established. -Chuck>

Yabbies
Hi I was thinking about purchasing a yabbie, and all the sites I have looked at have said nothing that can help me.  I was wondering how much space and how many gallons would be needed for 1 yabbie. -Cristi
<Hey Christi, if I were to house one yabbie I would not go any smaller than a 10gal.  I have 4 in a 29gal that have bred and so far the young are growing up healthy and happy, I am amazed there are still some left, these guys have not problem eating their own.  I do have problems with aggression and will be moving them to a larger tank soon.  I like to feed mine the clippings from my plant tank, these guys love live plants.  Best Regards, Gage>

I Love to Eat Them Yabbies!
>Hmm...I aimed my last note at Sabrina, but now I suspect it is Marina who is the Crayfish lover
>>Umm... I am, but I love to EAT them. I know a little bit, though.
>...anyway, any help, from any of the crew, regarding the odd-angled leg, much appreciated,
Andy
>>A Crawdaddy with an oddly-angled leg? Post molt, maybe? You could actually just pinch it off, and it'll grow back with the next molt. Same thing with the claws, if it's getting too aggressive, just take 'em off (with the bigger ones I'd use some kitchen shears to get a clean cut). Sounds awful, but they encounter lost limbs all the time in nature (do it to each other, you see) and have ways of dealing with it. Know that such inverts appreciate having "biominerals" available; iodine and calcium are what's needed to proper shell formation and the like. You may want to test your water, though I couldn't tell you what proper levels for a freshie would be (iodine), and calcium.. hhhmm.. I know I'd like it to be in the range of, oh.. say 350-400 (tested on a calcium kit), but don't know if that's what we're shooting for fresh, either. I'll suggest at this point that you ask the folks at ThePlantedTank.com, I think there may be someone who knows. Marina 

This Yabbies Ain't For Eatin'!
>Thanks Marina...
>>You're welcome Andy.
>I append the full note explaining the leg thang. Gage reckons leave it alone. I just am not sure what's best. Any further advice much appreciated.
>>Sure thing.
>Here we go:
I have a little blue crayfish, nearly 3" long, 2 years old, called Lopez.
>>Aahh.. a blue.  These animals are more inbred, and thus more prone to such problems.
>At the last molt (Sunday) he got a let stuck and when he finally got it out, the leg/pincer was at an odd angle, kind of backwards, clumsy looking.
>>Alright.
>He is moving and eating (lots) and can still use the leg and pincer, but it is certainly not right. It is bent backwards and gets in his way when he tries to hide in his jar/burrow, though he gets in in the end. I am wondering whether to somehow tweak it off (ouch) so he can grow a new one. But really, I am scared to hurt him and would rather think he will be fine and that he is not in pain as he is.
>>I don't think he's in pain at all.  Remember when I told you how these animals lose limbs all the time?  It's true, and this is no more harmful to them (to lose one or two) than a lizard its tail.  It causes them little to no distress.  When I was working import/export it was standard to remove the claws of the larger animals, or else they'd tear apart those with smaller claws.  As I said before, a pair of kitchen shears would make it clean and FAST.  No worries, really, just do it at the joint.  This would allow Lopes (I love that name) less struggle with regrowth and shedding of the new limb.  In the meantime, let's do be sure he's not in need for iodine or calcium, as I mentioned before.
>What do you think? How can I tell?
>>Well, we can't really tell, it would be difficult to see things as Lopez does.  But, what's natural for him isn't quite natural for us and vice versa.  If I were close by I'd come and do it myself, it literally takes less than a moment.
>And if you think I really must tweak it off, any advice on how to do so...??
>>If he's got large pincers, then take him up with a towel, he can be out of water just fine.  Take those shears, aim, and SNIP!  Quick as that.  Then, put him back, give him a hot dog or some such treat (maybe a bit of shrimp, that would be a good source of iodine, eh?  Raw, please) and he'll forget about it before you do.  Then, watch out for future molt issues, it may indicate need for biominerals, as mentioned before.
>I really like this little fellow and want to do my best for him. Any help
appreciated.
Cheers, Andy
>>No worries, Andy.  He's not competing for food with anyone, so as long as he's not really struggling (if you lose your nerve to snip the dicky leg) and feeding he should be fine.  Marina

Blue Marron covered in Algae
Hi, hope you can help. I've had a blue marron for a year now. In the first 2 months he molted twice and hasn't done so since. Now it looks like he may have external parasites on him, 1/4" long white worms, that stay in one spot but do sway in different directions. I also have a huge algae problem in my tank (72 gal) and now the marron is covered in algae too. I do water changes twice a week, vacuum the gravel, clean the filter (Fluval 304)every month.
I have several large fish, 18" Pleco, 10" iridescent shark, and various other catfish. The fish get a diet of algae wafers, shrimp pellets, flake and sometimes fresh greens. There are also many live plants in the tank which grow at lightning speed, I have to keep cutting them back. The marron seems happy enough, eats well and travels the tank, I just wish he looked good again. Thanks Taru
<Check the ammonia , nitrites and nitrates. The ammonia and nitrites should be zero. The nitrates should be under 25 ppm. If the nitrates are above the 25 ppm range then you may need to clean the filter more often and change more water. The parasite will be difficult to treat since the medication may affect the blue marron.-Chuck.> 

Please Help I Don't Know How To Take Care Of My Pet Craw Fish
Hi My friend just gave me a baby crawfish he is no bigger than 2 and 1/2 cm and he is in a small glass aquarium that's about a pint and a half . I don't know much about crawfish and neither did my friend. I just got over a loss of my pet rat so I felt that maybe taking the crawfish would make me feel better. 
I told my friend Lexi about him and she told me that she once had some pet crawfish she said that they basically eat dog bones and she said that you u have to put fish chemicals in the water so I did but that's all she really said. 
Here is what I put in the water... 2 drops of Aquari-sol and 1/8 tsp (6ml) of Tetra Aqua (Easy Balance water conditioner for fresh water aquariums) (eliminates frequent water changes). 
My mom basically said that's what I should put. I don't know anything about crawfish so I wanted to know if u can help me and tell me how to take care of them and if I am doing anything wrong. I didn't put any plants or rocks in it should I? Thank you for your time sincerely, Andy Ruvolo
<Have a read here: http://www.wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm and the linked files at the bottom. Bob Fenner> 

Plastic Plants and Crawdads 6.11.05
Hello,
I found you website using Google when I searched for crawdad pet info and was amazed at what I found here.
I spent the a couple of hours enjoying the info you and your members had to offer.
I am writing because I just received six - 1 inch crawdads from a local pet store.
they now reside in a 15 gallon tank with only four feeder goldfish.
I assume the conditions are fine for both groups. my concern is, in all of the material I have read so far I have not come across wither plastic plants will be eaten by crawdads, and if so can they be harmful?
If you have any info on this subject, or can suggest a source for this info I would appreciate it.
<As your crawdads grow they will most likely fight and kill each other, they are very aggressive towards each other and a 15 gallon tank is not terribly large.  I had that problem in a 20gallon tank with 4 crawdads.  Provide a lot of hiding spaces to reduce the aggression.  I have been keeping crawdads for a few years now and have never had a problem with them eating plastic plants, I am sure they know it tastes like plastic and is not yummy.  Your crawdads and goldfish both would appreciate some Anacharis (also known as Elodea), it is pretty cheap both critters would be happy to munch on it.  Best Regards, Gage>
thank you, Ryan