Oscar with lobster, comp.    8/12/07
I'm hoping this email will go through at this address, I can't find the address to write to you but I see thousands of FAQ's on your sight where people have emailed you.
My question... my 2" Oscar is going from his 40 gal tank into a 90 gal next week. I'm looking for a different or unusual tankmate.
The blue cobalt lobster gets to 5" in a freshwater tank and is said to
be non-aggressive to fish too big to eat. Do you think I'd have a problem putting a 2" blue cobalt lobster in with my 2" Oscar? I don't want my Oscar hurt but I also don't want to treat him to a $50
meal either, I'd like them to become tankmates.
Is it a good idea?
I've been reading your sight non-stop for 3 days and I love it!
Thank you so much,
Mitzi Potter
Oklahoma
<I do think this could work out splendidly... Do make sure there are plenty of rocky spaces for your Lobster to hide while it periodically molts (lest it be eaten by the Oscar then). Cheers, Bob Fenner>

Re: Oscar with lobster  8/13/07
I appreciate your answer more than you know, Bob.
I've also researched the Blue Knight Lobster (a 2" one) to put in with my 2" Oscar. Said to get about 12", have smaller claws and seem not to chase fish because they're too slow to catch them.
If that's actually the case I'd like to go with one of them instead based on your opinion
My concern is whether a 90 gal is big enough for an adult Oscar and an adult Blue Knight Lobster (no other inhabitants). If you think 90 gal isn't enough, I'll go with the Blue Cobalt.
<Is large enough for either combo.>
One thing I've gathered about your sight is that you all will actually know whereas other places often don't. So while I hesitate to bother you again, I value your opinion.
Mitzi Potter
Oklahoma
<No worries. Bob Fenner, who has kept a few species of Crayfish...>

Re: Oscar with lobster 2  8/13/07
Don't bother answering this message I sent earlier. I've decided I don't want a lobster as big as my Oscar (slow & small-clawed or not).
That's just too big of a risk to my Oscar.
Thanks for your time and have a great day!
Mitzi
Oklahoma
<Okay... RMF>

Oscar with blue crayfish   8/18/07
I'd asked your advice last week about adding a 2" blue crayfish to the 90 gal tank I was moving my 2" Oscar into. You were quite helpful and said it should work nicely.
I bought a 2" blue crayfish who's in quarantine right now. I asked the fish shop owner if the iodine (that crayfish need) would hurt the Oscar. She told me #1 that crayfish don't need iodine and #2
that yes-it would kill my Oscar. Ok....so now I'm thinking I don't really trust what the fish shop said because I do know crayfish need iodine (or am I wrong?) I've looked on your sight and can't find whether the iodine would hurt my Oscar or not.
Could you tell me whether iodine would hurt my Oscar?
Also, how much iodine does my crayfish need?
I want to do this right but I'm having a heck of a time with getting the correct information from different fish shops. Your sight is truly the only one I trust.
Thank you for your time, I know you're in high demand :-)
Mitzi
<Hello Mitzi. I'm going to disagree with whoever told you an Oscar and a crayfish will get on. They won't. Guess what Oscars mostly eat in the wild? Correct! Crayfish. Also crabs, shrimps, and snails. Basically anything with a shell. Contrary to popular belief, wild Oscars don't eat a lot of small fish. They are too slow to catch them. But their excellent eyesight and very strong jaws are perfect for finding and crushing shelled invertebrates. So, sooner or later, your Oscar will view a crayfish as food. (Of course, this also tells you another thing: the correct diet for Oscars is not based on fish, but on crustaceans and molluscs. But don't get me started on how unhealthy feeder fish are as a diet for Oscars!) Anyway, I have no idea why you need to add iodine to the aquarium. Crayfish are omnivores, leaning towards herbivores. In the wild they feed principally on decaying plant material and algae, supplementing that with carrion, i.e., the odd dead fish. A similar diet in the aquarium should give them all the nutrients they need. Using foods based on algae, such as Sushi Nori or algae wafers, should provide ample iodine. Giving your crayfish some marine invertebrates or fish, like krill or lancefish, once a week will provide the other minerals they need as well, such as calcium. What does matter is that the water is at least moderately hard and not acidic. Crayfish, like other shelled invertebrates, are more prone to problems in soft and acidic water. Bottom line, your crayfish needs its own ~10 gallon tank, where you can feed it plant material six days a week and a meaty treat on Sunday. Cheers, Neale.>

Re: Oscar with blue crayfish   8/19/07
Hi Neale.
Bob Fenner is who said they'd be good tankmates (the crayfish gets to about 5" and they're both starting off at the same 2 size-too big for the Oscar to eat). They'll be in a 90 gal tank. And Sabrina (on your sight) is who has stated many many times that they need iodine, she has crayfish. With all due respect the crayfish gets far too big (in my opinion) for a 10 gal tank. My water is
perfect for both crayfish & Oscars straight out of the tap (lucky me).
So I'm back to square 1 it seems, aren't I? Not sure where to go from here aside from more research. Thank you for your time :-)
Mitzi
<Hello Mitzi. There's plenty of scientific research on rearing crayfish, since they're a valuable crop in many parts of the world. So finding out objective information about rearing these animals should be easy. I have absolutely no doubt about Oscars eating crayfish -- please visit Fishbase and you can read that yourself. It's the second item on their list of preferred prey! Obviously what matters is the size difference, if any. But the common species of crayfish sold as pets stay quite small, but Oscars get quite big, so sooner or later... The problem isn't so much day to day, but when the crayfish moults. When that happens, it has no defence, and the Oscar might decide to have a nibble. As for the size of the tank, that naturally depends on the species being kept. There are small crayfish and there are big crayfish. I cannot possibly know which one you have. But the small Astacus type things widely used as lab animals are fine in 10 gallon tanks. But a 20 cm Cherax quadricarinatus will obviously need something bigger. I have no idea why Sabrina reckons they need extra iodine. But I imagine the major problem experience by aquarists keeping crayfish may be dietary, and specifically problems with lack of green food. But crayfish are incredibly easy to look after, and in their own tanks are basically indestructible. Where people go wrong is the lack of greens and, in the case of coldwater species, too much heat. (A lot of the supposedly tropical species are actually subtropical or coldwater, so get the Latin name of your species to confirm this either way.) Bottom line, I'd consider mixing any fish with a crayfish a gamble at best, with both the fish and the crustacean running the risk of being attacked and/or eaten depending on the circumstances. Your move. Cheers, Neale>
<<RMF is still of the opinion that (given cover for hiding during molts) that these species could co-habitate. Oh, and do need iodide>>

Re: Oscar with blue crayfish – 8/19/07
Hello, Crew,
Neale, you'd asked the Latin name for this crayfish, it's Procambarus sp.
<Mmm, will send this along to Neale as well... Maybe Procambarus clarkii... the most common (of a few hundred) species of Crawfish in N. America... and the principal animal of human consumption by this name.>
Bob, thanks. I'm of the opinion they'd be good tankmates in a 90 gal also.
<Mmm, maybe not "good", but good-enough odds for a likely mix... I do agree with Neale re the penchant for most Astronotus to ingest such shellfish... but given the starting size of both, enough space and cover... I would give better than 50% odds of them getting along>
The crayfish will have his choice of 8-10 rock caves and holes too small for the Oscar to get into for when he
molts. I wanted some sort of 'living creature' in there with my Oscar so he wouldn't feel totally isolated. But not another fish he felt the need to compete with. I think a blue crayfish is a good
choice and will go ahead with that.
I guess it's a matter of getting opinions, weighing the pros and cons, making it safe for both then going ahead with what each person believes is a good move. Sounds too much like "life" to me
<g>.
Thanks all,
Mitzi
<Do please keep us informed re the ongoing... BobF>

Crawfish and Shrimp – 06/14/07
Howdy.
< Ave.>
> I have 2 10 gallon tanks. One of them holds my 4"inch crawfish, Bojan and four (used to be 5) guppy "friends". He is happy and healthy and hilarious.
< So, you have discovered that crayfish can and do eat small fish, given the chance.>
> The other tank holds 3 Cory catfish, a couple of guppies and three TINY crawfish (one temporarily named "grain of rice") which I know will get bigger and will need to be either moved to separate tanks, or returned to the creek from whence they came.
< Returning animals "to the wild" is at least the wrong thing to do, and at worst illegal. If in doubt,
<<My value systems switch these. RMF>>
consult with your local Fish & Wildlife Bureau. The problem is that those crayfish have no been exposed to pathogens and bacteria than native crayfish (and other aquatic organisms) may have no resistance to. American crayfish got loose in the UK, likely from farms, and carried a fungal disease that has basically wiped out our native crayfish. The American crayfish is somewhat resistant, and so takes over vacated territory. See here: http://www.defra.gov.uk/fish/freshwater/crayfish.htm . Moral of the story: never, ever release captive animals back into the wild.>
> Here is my question. My friend has the cutest little ghost shrimp. I was thinking of getting some to put in with the Corys and baby crawfish. I am guessing that ghost shrimp and crawfish are not compatible, but thought I would ask you guys and gals to see what you thought. If these two are not compatible, are there any shrimp that would be compatible with baby crawfish or would I need to choose between having crawfish or having shrimp? (What a delicious question!)
> Thanks!
< Crayfish and small shrimp are indeed incompatible. Crayfish are omnivores, feeding primarily on plant material and detritus, but small animals are also on the menu. In the confines of an aquarium their clumsiness isn't a problem, and eventually they corner smaller tankmates, usually at night. Obviously baby crayfish smaller than the shrimps won't be much of a problem, but as the crayfish grow, expect them to become more predatory *and* more territorial towards one another. The only shrimps I would keep with crayfish would be large Macrobrachium spp, (Freshwater Tiger Prawns) because they are pretty nasty animals themselves. Given crayfish don't move about much, I personally think they look best kept in their own small aquarium. Cheers, Neale.>

Goldfish and crayfish  – 05/16/07
I have two goldfish in with my crayfish. The goldfish are much larger then the crayfish. The question will he still try to eat them?
<While crayfish are primarily plant eaters and scavengers in the wild, given the chance, they will eat any fish they can catch. In aquaria they can and do trap fishes in the corner of the tank. In a sufficiently large (deep) aquarium regular goldfish might be speedy enough to avoid problems, especially when fully grown, but fancy goldfish are much more vulnerable because they can't swim well. On balance, I'd suggest keeping them separately. Cheers, Neale>

Question about Crayfish and their compatibility with Cichlids    5/15/07
Hello,
<Hi there>
We just purchased a 20 gallon aquarium (no fish yet) and were interested in purchasing a Crayfish -
<You are aware of how predaceous these are?>
a woman at my work has one and it sounds like a really fun and very interesting pet!  The blue crayfish in particular has caught our attention.  We would like to get other fish for the tank but since crayfish are known to be aggressive toward slower and smaller fish, we wanted to be careful with what other fish we got.  Cichlids in particular seem to interest us,
<Not enough room here for a crayfish and any Cichlid species that would likely survive its presence>
and we read that they are aggressive fish as well which supposedly is compatible with crayfish's personality.  Would these actually be compatible with a crayfish?
<Some could be mixed in a much larger volume... Not twenty gallons though>
Also, we hear that Cichlids are best purchased in large groups, and so we were also wondering if 6 + a crayfish in a 20 gallon tank would be overcrowded?
<For most all species available (there are hundreds worldwide, even hundreds described just in the U.S.), you'll end up with one, maybe two... and a bunch of parts...>
Thank you so much!
--
Laina VanDyke
<Please read here: http://www.wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm
and the linked files at the bottom. Bob Fenner>

Blue crawfish, comp.   5/9/07
Hi! Just a quick question. I have recently been given a blue crawfish from someone who bought it and then had second thoughts-thus, we I have inherited it! We have a 30 gallon tank with a few guppies, a few danios, 6 tetras, and a 6 inch plecostomus and an 8 inch plecostomus.
The crawfish seems okay with them all,
<Will in time consume all...>
but chases the large plecostomus' out of their fake log hiding place. We have put a few rocks for the crawfish to burrow under but he goes in the other guys' house. Do we need more shelters? Thanks a lot!
Diane
<You need another system to separately house this crustacean... Please read here: http://www.wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm
and the linked files at bottom. Bob Fenner>

Re: blue crawfish   5/10/07
Thanks so much for the information. A new setup will be good, for I don't want to lose my other fish! Thanks again!
<Ah, you're welcome. BobF>

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

Salamanders:   1/19/07
These guys came from the same stream (empties into large lake) and one is more developed at ~4 inches, tiny white spots riddle his black skin.
We're in Georgia so I can't figure out what kind he is (Dusky? Eastern?). While I know the variations must be incredible, but lets say he is a common eastern salamander - no color on fingers or underbelly, just the white speckling - what do you think he could be?
<Mineral deposit maybe, perhaps decomposition from being moved into too-warm setting/out of season>
Three younger ones accompany him and still have their aquatic lungs exposed and paddle-like tail. They are about ~2 inches each.  The last one I caught actually resembles the grown salamander which led me to deduce they may actually be the same species, but separate in amphibian maturity.  
<Maybe>
Will these guys fare well in captivity (with the four baby crayfish)?
<Not indefinitely... unless there is a good deal of room, habitat>
Given the same environment I tried to recreate, the cascading waterfall filter, aeration, native water, rocks, moss, and inhabitants, will they be able to fend for themselves given we feed them regularly and keep the conditions clean?
<For a while>
We recently caught some minnows/guppies (feeder size) from the same environ (downstream of lake - amphibians and crayfish were upstream), would the salamanders ever be able to catch one of these?
<Not likely>
Also, I caught two grubs (ginormous, condensed to an inch long fat grub and extended to over 2 inches of sprawling larvae mass) and thought they'd make good food for the carnivores.
<Mmm, none of the animals listed are "very" carnivorous when young/small...>
But then, I was experimenting, and fed them all (within first couple days captivity) a bite of raw ground turkey. I placed a tiny morsel at their hiding spot entrances and they devoured it.  How much should I feed them for a daily (or every other day) dose?
<Depends on temperature... but very little daily... do monitor water quality...>
I'm  less worried about them. The matured salamander, I am afraid, is the more picky the eater. Should I attempt crickets?
<No>
Also, how much terrestrial space should I provide? As of now, there are but 3 islands (larger rocks jut out (with moss encropped) around the waterfall, and another smaller at opposite end juts out next to a floating stick from their environ.  Should I provide more?
<Mmm, not in this size/volume>
I was hesitant to expand for fear for trapping someone in hiding, but know they are all well equipped and evolved to find another way out. I wanted to bring in a few more larger stones to extend the terrestrial portion so he will have at least a foot (1 foot by .5 foot) length of crawl space.
<Not much land space needed, advised>
Any vegetation they prefer?
<What you find in their wild environs>
I put in some green moss last night and he's been buried under it ever since (before he was hiding out of the water behind the filter). I like seeing him more comfortable under the moss and in and out of the rock/water crevices than pinned against glass and plastic filter backing.
Also, please expand any further on suggestions to make sure they have a good stay or what other inhabitants they'd like (more minnows or bugs per chance).
<Wish I could... a matter of your investigating... the Net, books... on local fauna... ecology>

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>

Treatment for a laceration injury; crayfish compatibility?   11/8/06
Hi--
<Hello Erica - Jorie here>
Our pictus cat has suffered a ~5mm gash on one side of its abdomen, probably thanks to Pinchy, our resident speckled crayfish.
<Probably so.  Pinchy will likely continue to damage your catfish, as well as other tank inhabitants, depending on what you've got in there...he will likely need to live in his own tank if you don't want to hurt your fish...)
  I'm wondering whether and how to treat the wound.  The cat has been pacing a bit (swimming back and forth) and its abdomen is slightly swollen.  Otherwise, its color and appetite appear to be ok.
<I would suggest isolating the injured fish, keeping water conditions clean and clear, and adding MelaFix to promote speedy tissue regrowth.  Keep a very close eye to ensure no secondary infection develops at the wound site - if it does, a broad spectrum antibiotic such as Spectrogram will help.  So long as the fish is swimming, eating, and otherwise behaving OK, I don't suggest anything but quarantine, clean water and MelaFix.>
Thanks in advance,
-Erica
<Jorie. Do try to find an alternative home for Pinchy.>

Re: Treatment for a laceration injury; crayfish compatibility?  11/12/06
Dear Jorie:
Thanks so much for the information!  The cat's doing much better now and seems to be on the way to a full recovery.
<I'm glad to hear that.>
Yes, we're looking into alternate arrangements for Pinchy.
<Love the name!! You must be a Simpsons fan, also...>
  She's been rather crabby and aggressive since having her first set of unsterilized eggs.  Perhaps a new, dedicated home and a boyfriend will help.  :-)
<Unfortunately, I know nothing about keeping crayfish, so I can't advise you here...do read up on proper conditions, incl. whether or not a mate would be suitable prior to purchasing...>
Thanks again,
-Erica
<You're welcome. Jorie>

Crayfish Compatibility and Breeding - 08/08/2006
Hello again,
<Hello!  Sorry about the delay....>
Everything has been going perfectly, the ghost shrimp we got from the store are surviving with the crays, and Mavra has molted again after 17 days.
<Awesome!>
She is now as close to Vladimir as she will ever be. I think now would be a good chance to attempt to mate them, after giving Mavra a few days to develop her shell. My mother only has one concern, that there will be around 200 baby crayfish that will grow up to become 5+ inches.
<Heeeeeeheeeeee!>
If there would be triple digit babies,
<NOT highly likely.>
is there any way to keep the numbers maybe to the double digits?
<They will probably limit themselves....  unless conditions are absolutely incredibly entirely perfect for them every step of the way.  And what to do with them?  Friends, family, fish stores, wholesalers!  Fun....>
We plan to purchase a new tank, move her into it so she is alone, then after a while, introduce Vladimir, and see what they do.
<Don't forget to dim the lights, put on some soft music....>
We will keep a spatula handy if they start to fight. Afterwards if they do mate, we would put Vlad back in the 15 gal. tank, which would now be 100% his. I have read that it could be up to a week before the eggs appear and around 3 to 4 weeks for the eggs to develop. I have researched heavily and am trying to get as prepared as possible for this huge event.
<How exciting for you!>
Crayfish owner and possibly new stepfather,  -Colin
<I hope to soon be congratulating you on crayfish babies!  All the best to you, Mavra, and Vladimir,  -Sabrina>

Crawfish and the community tank 5/8/06
I recently found a crawfish on the road and seeing how it is Missouri and the creeks will soon be dry I took him home. I want to put him in my 20 gallon tank but curious as to how well he will survive.
<He'll do fine, his tankmates will not.>
He is only about 3 inches long ( not including pinchers ) but I have mollies,
<crawfish food>
a Plecostomus?,
<food unless larger than the crawfish>
and an African claw frog
<food>
in there already. I don't want him to kill my fish nor do I want him hurt.
<He will eat whatever he can catch.>
Also do they have to be able to get out of the water or can they live totally submerged all the time?
<Submerged>
My twenty gallon tank is tall not long. Also I have live plants in my aquarium will they hurt him?
<No.>
Thanks
<Welcome.>
Julie O.
<Chris>

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>

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>

"A Craw-Fish by any other Name would Chew Plants..."
Mr. Fenner:
I am in the early stages of preparation for building my first community tank. I am planning a 35-Gal tank with many live plants and two species of schooling middle fish, one species of surface fish, and an additional species of bottom-feeding/pleco-type fish. Is this feasible?
<Sure>
My main concern is this: I feel that in the future I may be unable to defend myself against the irresistible charms of lobsters and crayfish. 
<They are delicious... prepared properly!>
Is there a place in a perfectly harmonic community tank for one of these invertebrates?
<Mmm, no, not really. There are some fresh to brackish crustaceans that are "better"... please read: http://www.wetwebmedia.com/shrimpfw.htm>
I hear that they have picky tastes in water pH and temperature, are destructive to aquatic landscaping, and can be determined to bust out and go AWOL. Is there a way to have fish AND yabbies?
<Again... not really... their tastes are actually "too cosmopolitan", and many species are known to be quite "eury" condition... adaptable to widely varying conditions... but most all what folks call "lobsters", crayfish, crawdads, ditch "bugs"... are all too destructive, fish-eating to be "harmonious" in a community tank... Maybe two tanks? Bob Fenner>
Please advise.

Freshwater Lobster
<Lorenzo Gonzalez standing in for Bob-in-Asia>
Hi, about three weeks ago I bought a blue freshwater lobster, and I know that it needs fairly hard water, do you know of any suitable tankmates for it? I hope
that there are some hard water cichlids that will be suitable for it, but I'm not too bothered if they aren't cichlids.
<Almost any Rift Lake Cichlid that won't get too big to eat it, and isn't too small to get eaten... will probably do fine. The larger S. American cichlids will happily eat the lobster, besides, most prefer softer water than their African relatives. Either way, most of these cichlids, and probably the lobster too, will likely be just fine with tapwater, if it isn't softened with a household softener (anathema to all fish, really) 
-Lorenzo>

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>

Lobster Attack
Hello, I recently purchased a black ghost and enjoy him. I had him with a pair of tiger barbs and a pair of iridescent sharks, and 1 lobster. When I went to check on him I saw the lobster had the knife fish in his claws. I separated them and the tail of the knife fish is badly injured. He is resting on the bottom on the tank on its side and sometimes on its back.  I took the lobster back to LFS and got an channel catfish. The Knife doesn't seem very well and was wondering what I can do to help him.  Thanks Pat
<<Dear Pat; good job on taking back the lobster. They are aggressive and are quite capable of trapping live fish in their claws. For the black ghost, you need to be sure to test your water. Test for ammonia (should be zero), nitrites (should be zero) and nitrates, as low as possible, around 20-60ppm is best. You need to be sure the water is clean to prevent secondary infections of the wound. You can also add some Melafix to the tank water, to help him heal up. I hope he was not internally damaged. How big is the tank? That channel cat will grow 2 feet long, almost as big as the iridescent sharks. -Gwen>>

Here comes another one, just like the other one
Hi I wrote to you last week but did not see an answer posted.  
<Wow, my deepest apologies!  We do try to get everything answered right away, I'm sorry this one fell through the cracks.>
My question is... can lobsters and snails live in the same tank?  The reason I ask is because two days after I put a snail in the tank with my lobster my lobster died.  He died on his feet, but the night before he died he had flipped over onto his back twice. Could it have been the ph? <Woah....  Dude....  De ja vu and a half!  I'm sure this is related to a correspondence I just had with another person about the exact same topic, but just in case, all the info again:  Assuming that the snails and 'lobster' are freshwater, as I was told in the other correspondence, I feel that the 'lobster' death is likely unrelated to the snails.  Test the water for ammonia, nitrite, nitrate, and pH; if any of these are out of whack, it could be what did in the little crustacean.  Your little lobster (actually, either a Macrobrachium shrimp or a crayfish) may possibly have just suffered a bad molt.  Sometimes, when they shed their old skins, the new shell doesn't harden properly or tears, or has some other sort of complication.  This is one of those things that can 'just happen'.  The best way to avoid it ever happening in the future is to dose the tank with iodine (I use Kent marine) at a rate of one drop per ten gallons every week.  Beyond this, the only risk in keeping these two animals together is to the snails - I wouldn't put it past the shrimp/crayfish to decide to dine on escargot some day.>
I would greatly appreciate any input. Thank you in advance!
Deysha Rivera
<Hope this gets to you properly, this time!  Wishing you well,  -Sabrina>

Murderous snails?
dear sir,
<Or maam?  ;)  Sabrina here today>
my boss has requested me to ask you for some information regarding snails and lobsters.  
<First chunk of info I need here - are we talking freshwater snails and lobsters, or saltwater snails and "lobsters" (crayfish, Macrobrachium shrimp)??>
You see, she recently put two snails into the same tank as her lobster.  
<Do you happen to know what kind of snails, and what kind of lobster?>
Three days later, the lobster was dead.  The day before he died, he was exhibiting sluggish behavior and even turned himself over onto his back twice?
<Two things come to mind; one, that he had a 'bad' molt and didn't survive it, or that water parameters were out of whack - what are/were your readings for pH, ammonia, nitrite, and nitrate (and salinity/specific gravity and calcium, if we're talking saltwater)?
Is it possible that the slugs murdered him with their deadly pH?  
<Uhm, I'm a touch confused, here....  snails, or slugs?  And by "their deadly pH" what do you mean, exactly?  Did the pH change after you added them?>
I would appreciate any input you have on the occurrence. Thank you for your time.
Cricket McLeod
p.s.
it was a little blue lobster.
<Just a touch more info (FW or SW, water parameters) will greatly help us to help you.  Wishing you well,  -Sabrina.>

Murderous snails? continued
He/she was a fresh water little blue lobster (well that is what the pet store told me anyway) about four inches long.
<Likely either a Macrobrachium shrimp or a blue crayfish then; a few species of these are often sold under the name "blue lobster".>
Fresh water snails also. I don't know what kind light brown in color, does that help?
<Since we're talking freshwater, I think the type/species of snail is irrelevant; there are a few marine snail-types that are quite venomous; although it'd have been a long shot, it was a thought.>
Not sure if the water was out of whack. I did not test it after adding them. Could the snails have altered the ph, ammonia, etc..?
<If one died, yes, but other than that, I'd think it far more likely that the water quality was going downhill (do you change water regularly, vacuum gravel, etc.? how big of a tank?) or that the 'lobster' simply had a bad molt.  This threat can be avoided (though not completely eliminated) by dosing the tank with Iodine (I use Kent marine) at a rate of one drop per ten gallons every week.>
But if all ph, ammonia, etc. is normal is there any reason they can not live together?
<Well, these (both the big arm shrimps and the crayfishes) are really equal opportunist eaters.  I remember as a kid feeding crayfish in a friend's pond stale potato chips (not a good idea, though!).  I might be concerned that the 'lobster' would decide to munch the snails, but that's the only issue I see with it.>
thank you again!
<Sure thing!  -Sabrina>

"Lobster"/snails continued
The "lobster" lost it's shell about two weeks prior to the addition of the snails. It ate it and all appeared fine after that.
<I would probably suspect water quality issues, then.>
If I do choose to purchase another one do I add the iodine after it losses the shell?
<Add the iodine weekly, every week, one drop per ten gallons.>
Surprisingly enough the "lobster" did not bother with the snails.
<It may be one of those things that it's just a matter of time, or they may live in harmony forever.>
Once again thank you I won't bother you any more.
<Not a bother!  That's what we're here for.  Wishing you well,  -Sabrina.>

Blue Water Lobster
Dear Bob
<Hey there - I'm not Bob, but I am the freshwater invert-obsessed Sabrina - hope I can shed some light on your new critter.>
We have a Blue fresh water Lobster but are having a few tiny problems with him/her and wonder if you may have any answers?
<Hmm....  I've seen a few different animals that fall under this name, any of which might be the critter you've got.  It could be any of a handful of Procambarus species (crayfish) that is blue or has a blue form; or could be either of two blue Macrobrachium shrimp species - M. rosenbergii from Thailand or another species from Mexico.  A picture would go a long way to identifying it, if you've got one.>
He is attacking the big Plec and ripping the Pleco's fins.  He has also started recently to kill the smaller fish by grabbing them with his claws.  
<For any of the species above, this is quite normal....  they don't play well with fish.>
Is there any way we can stop this?  
<No, not really.  Separating him from the fish is pretty much the only way to end the carnage.>
We have now put in a ceramic pot and cave entrance to give him a safe cover, will this help combat the problem?
<No, unfortunately.  Regardless of which of the above critters it is - they're aggressive, and fish-hungry.>
We feed him on prawns
<Excellent food for 'em>
and specially bought crab cuisine which states is ok for Lobsters.  Should we be feeding him anything else?
<Ocean Nutrition's frozen Formula One is a good food choice.>
We have looked everywhere for a book on Lobsters but have had no luck.  
<Do some google searches on 'blue crayfish' and 'blue prawn', as well as the above Latin names.>
He is now about 4 inches long without counting the claws.  
<And will grow about twice that>
He is shedding about every three to four months and eats his shell afterwards.  We have had him now for ten months and has shed three times.  He is showing signs of being due for another shed as he is constantly laying on his side and acting as though he is dead, which we have noticed he does this just prior to shedding in the past.
<I don't think that's a good sign....  perhaps try adding iodine to the tank (use Kent's marine Iodine supplement); one drop per ten gallons every week.>
He is constantly shoveling the stones about, we have had to change from a sand bottom as he kept blocking the filter with the constant moving of the sand.  We now have an undergravel filter.  If you have any information that will help our Lobster Rocky to have a good life, would you please be so kind and inform us?  
<I am sorry for the news that he'll be always incompatible with most fish; he may warrant a tank of his own.  There are a few fish compatible with these animals; do some google searches to try to find out exactly what you've got, and hopefully that'll help you out some.  Wishing you well,  -Sabrina>
Thank you in anticipation.  Yours sincerely  Mr. John Edwards

Crayfish in a Pond
Hi, I was reading some articles on your web. My husband and I have put in a pond in our back yard and were wondering if we could add a few crawdads and what we do if we can. Is it possible and what would we need?
<Certainly this is possible.  If you have any slow moving or small fish, however, they'll likely become food for the crayfish (crawdads, crayfish, po-TA-toe, po-TAH-toe....  same difference).  They're pretty equal-opportunist eaters; I'd suggest feeding with something that sinks quickly, to prevent your fish from getting the food before the crayfish, which would starve the crayfish and force them to snack on your pond fish.>
Do they crawl out?
<Not really; it'd be a good idea to keep the water level a touch low, just in case.>
Could you give us some ideas? We live in the Eastern Sierra Mountains in Ca.
<Look into what species are native in your area, for best results.>
Thank-You  Sandi
<Any time.  -Sabrina>

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

Crayfish Reputations? - 09/11/2005
We have a 70 gallon fresh water tank. About a year or so ago we bought a small blue lobster (Procambarus alleni?)
<Likely, but other possibilities as well.>
about 1.5 inches long. It's now a least 3 times that big and tremendously fun to watch.  
<They're great, aren't they?>
Although there are said to not catch fish,
<Who said?  These and other crays are quite capable of turning fish into food....>
I've started to notice that fish sometimes disappear. Do we have to choose between having fish or the lobster.
<Mm, possibly; otherwise, have fish that are large enough (or fast enough) to not interest the Cray as meals.>
If we no longer have fish, what and how much do we feed the lobster?
<Greens (aquarium plants like anacharis/elodea/Egeria), thawed frozen uncooked shrimp, sinking fish foods....  lots of options.  I would feed once every two or three days, probably.>
I'd appreciate any advice you can give us.
<You might consider getting him/her a mate and enjoy the fun of breeding these guys.  Our crewmember Gage (awesome guy) wrote a great article on Cray behaviour, feeding, breeding, etc.:  http://www.wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm .>
Susie
<Wishing you well,  -Sabrina>  

Crayfish Reputations? - II - 09/13/2005
Thank you very much for your fast response.
<You bet.>
Gage Hartford's article was great.
<Ah!  Glad you enjoyed it; I'll tell him.>
The only thing I still had a question about is the ph level they like.
<Extremely variable....  Don't drop 'em below 6.8 if possible - they can go above 8.0 with no real adverse reactions.  Wishing you well,  -Sabrina>

Crayfish Food? - 09/11/2005
I saw some crayfish at my local PetCo and was considering picking up one.  I have read about them, and for the most part there is ample warning that crayfish are semi-aggressive
<Not exactly "aggressive", just "hungry".>
and will eat any fish small and slow enough for it to catch.  
<True.>
I need a bit more information than that.  Would Otocinclus and other bottom-dwellers like clown loaches or catfish count?  
<Yes, especially the otos.>
I also have some Singapore (aka wood, bamboo, etc) shrimp.  How would they fare?  
<Less apt than the otos to become food, but still potential Cray food.>
I have a 75 gallon tank and there's plenty of room.
<You could try it, but realistically, you will probably lose some fish to the Cray.  You could try other peaceful shrimp, though, like Atya gabonensis (another filter-feeder like the wood/Atyopsis moluccensis).  Be sure to avoid those loveable "blue prawns", Macrobrachium rosenbergii, as they will decimate anything and everything in the tank that isn't large enough to eat them first.  Definately take a look here:  http://www.wetwebmedia.com/ca/cav1i4/crayfish/crayfish.htm - I know Gage's crays never bothered his common guppies.  Wishing you well,  -Sabrina>

Crawfish With Other Fish-Not For Long  11/11/05
I was wondering if crayfish pose any threat to fish or dwarf frogs,
<Absolutely>
both are smaller than the crayfish by a lot.
< Crawfish are excellent hunters. Those large claws aren't for show.>
I also have goldfish which are slightly bigger.  Also, is there anything you can tell me about crayfish,  Are they territorial?
< You can keep more than one in a tank. They will fight too. The biggest problem is when they shed their exoskeleton. For a while after they shed their outer shell they are very soft and tender. Other crawfish will go after them and try to eat them before their shell hardens up and they are able to defend themselves.>
Can you keep more than one in a ten gallon tank?
< I think one would be plenty.-Chuck>

Crays and Crabs? Nope. How 'bout Coldwater Flounders? - 11/27/2005
Hello.
<Hi.>
I have been thinking about setting up a 10 gallon aquarium for a blue Marron. I would like your advice on whether the crayfish would be compatible with one or more fiddler crabs.
<Nope. Fiddlers all require fully marine conditions to survive long-term. It is truly a shame that they are sold (doomed) as freshwater animals. Though they'll keep tickin' for a few months with only freshwater access, it's not something that can last. More importantly, though, they absolutely MUST have land access.>
I am also wondering if the two species are fairly easy to keep and if they are hardy since the blue Marron is very expensive in my area. I do have one more question for you Mr. Fenner.
<Whups, you got me, Sabrina, today. Bob's out of the country right now.>
I have purchased a fresh water flounder (very small less at most 1/2 inch long) today at my LFS and the worker told me it was from British Columbia.
<Mm, I find this rather unlikely. The "flounders" available for sale in the aquarium trade are typically tropical animals, though a quick search on freshwater flounders of BC brought me this:  Oregon State University piece . Here's the fishbase on this animal: Fishbase on a flounder. But probably, your animal is one of these:  http://www.wetwebmedia.com/FWSubWebIndex/fwflounders.htm . 
If it IS the fellow from BC, an aquarium in your refrigerator might be ideal - this animal would not survive long at all in the temperatures needed for tropical aquaria.>
She also told me it will only grow up to 4 inches long.
<Better be hoping it's not that P. stellatus, then. That fish gets about three feet in length. I'd keep your fingers crossed that it's the one species of actually freshwater tropical flounder that we see often in the trade.>
My question for you is do you know what this fish will eat, what kind of environment it likes, if it truly is like she said a freshwater flounder and finally if it will kill the rest of my fish (tetras and white clouds minnows)? 
<If it isn't obvious yet, please understand that you really must research an animal PRIOR to purchase, so you can be prepared for these things. The tropical flounders offered in the trade rarely take anything other than live foods, though you might have some luck getting them onto frozen meaty foods like bloodworms. As to its environment, I'd recommend you look at the species mentioned in Bob's article above and look them up (in Fishbase, Google, wherever you like) to find out more about each.>
Thank you for your time. 
<Sure thing.>
-Marcin.
PS. I would like to clarify that the worker in the store told me that the flounder is interesting because it can be acclimated to freshwater, brackish water, and marine water. I did not take this too seriously because it sounds like this is highly unlikely.
<Apparently the fellow from BC starts in freshwater, but by the time it's several inches in length, prefers increasingly brackish conditions. Again, I'm holding out a hope that it's not a large coldwater animal, or it and all the others the store is selling are, like the fiddlers, pretty much doomed. Please learn, and pass on the information you find so that others may learn - soon, you may be teaching the folks at your fish store. All the best to you, -Sabrina>

Blue Crayfish mis-mixed with African Cichlids    1/25/06
Hi there,
<Hello>
I just bought a blue crayfish from my local fish store this past Friday. He is in a 20 gallon tank with 4 smaller African Cichlids and a small pleco.
<Too small...>
For the first three days after I put him in the tank he really seemed to enjoy wandering around the tank and exploring the decorations. The fish
bothered him a little bit at first, but they are starting to learn their lesson. When I came home today I realized I could not find the crayfish. I
checked his usual hiding spots and when I lifted up the castle (which has an opening just large enough for him to fit through) I found one of his antenna
in the gravel. I freaked out thinking one of my fish had ate him. I turned the castle on its side and eventually found him curled up where I could not
see him. He has not come out of the castle at all today. Is he molting or is he just being shy? Should I be concerned?
<I would be concerned... the Africans are harassing the crustacean... and will likely do so to its demise. It needs other quarters. Bob Fenner>
Thanks so much,
Chris