Procambarus Clarkii, stkg. comp.     2/25/13
Hello,
I purchased seven large Procambarus Clarkii a few days ago and placed them in a 55 gallon aquarium.
<Mmm, I did a report in college re this species "substrate size preference" and have kept them as pets, and eaten quite a few at "crawdad bakes"...
They will attack and eat each other... till there is an ongoing balance re space, hiding areas and food availability>
The aquarium has aeration, filtration, and places for hiding.
On the second morning I noticed that one of the crayfish had been half eaten.
<Ahh!>
 The tail was eaten first then the rest of the crayfish was consumed over a 24 hour period.  The next day I noticed two more met the same fate.
<AH yes>
I have provided food in the form of vegetables and shrimp every day. I am becoming concerned about this behavior because I have lost 3 of the original seven to date.
I would like to know what is causing this behavior and how it can be prevented. Any help that you can provide would be greatly appreciated.
<Tis natural... folks who raise this species for human consumption purposely add fertilizer, make conditions that obscure water clarity, to reduce this sort of aggression. I would add more clay flower pots, PVC pipe/parts et al. to slow down the rate of attrition. You may be "at it" w/ the present stocking level. Enjoy the remaining individuals>
Richard
<Bob Fenner>
Re: Procambarus Clarkii, stkg.      2/26/13
Thank you for your help. I have modified the environment and hope this will correct the problem.
Richard
<Ahh; I do hope so. B>

Florida blue, too much stress?     1/12/13
Hello, Sylvi here!
<Hello Sylvi,>
I have a major problem with my female, Orion. She came to me with one claw smaller, obviously slowly regrowing.
<Correct, and may never reach full size. Crustaceans don't moult to order. They moult periodically as they grow. They moult frequently when young; infrequently when sexually mature. Eventually they all but stop moulting altogether. So, if your crayfish is fully grown, it may moult only every few months, in which case the claw will always be relatively small.>
I noticed her carrying a bundle of eggs a few days ago (I'm not sure how fast the laying process is, I was very surprised to suddenly see "her" with eggs). Last night, my large male Boris was really restless and constantly trying to invade Orion's safety cave, even though his regular cave was empty along with two other caves. This morning I found Orion cowering in a corner, her regular claw ripped off, by Boris of course.
<Hmm… confused here. Why are you keeping them altogether? Standard operating practise is to keep crayfish one to a tank. If you keep multiple specimens in one large aquarium, then don't go naming any of them -- because their lives are likely to be short and brutal. What more to say? Understand that crayfish aren't sociable animals, and keep them accordingly. Kept in solitary, 5-10 gallons per specimen, and such intraspecific aggression, even cannibalism, will be avoided. Simple.>
I separated her from the other two large males, leaving only a two inch female, and a one incher, with a few fish to keep the balance. My concern is, with only a smaller regrowing claw, carrying eggs, and having a claw ripped off, will she survive this trauma along with her eggs??
<Wouldn't put money on it. Crayfish are largely herbivorous in the wild, but they are completely opportunistic as well, so anything dead or weak is on the menu. Being nocturnal, we rarely see them doing much, which is why people often say things like "my crayfish is completely peaceful, it ignores all its tankmates". People can say that, but it isn't true, and unless you're watching your crayfish with night-vision goggles, you really don't have any idea what your crayfish are doing.>
I've been trying to feed her some greens, bloodworms, defrosted feeding fish, and brine shrimp, but i haven't seen her eating yet....so I'm very worried right now. Please tell me what I can do to make her as comfortable as possible and have her eating again! Thank you so much!
<Easy. Keep her on her own. Problem solved. Once in such an aquarium, she will recover if not too far gone, damaged.>
PS: The two inch "female" Rorschach started carrying eggs about 10 days ago, but I noticed her reaching back and snacking on her own eggs as if they were M&M's, and currently she only has about 5 eggs left, but they are a strange light brown color. Is this why she ate them? Or the other way around?
<Stress causes female animals to do all sorts of apparently odd things. But in terms of biology, eating your young makes complete sense if you are so stressed you know for sure your young won't survive. By recycling the energy put into those eggs, that female can conserve that energy for another occasion. Again, keep crayfish singly. This has been gone into over and over again, and yet people do try to re-invent the wheel when it comes to crayfish keeping. They just aren't trustworthy, sociable animals. If you keep a group, expect fatalities, and don't be surprised if you end up with a single, big male. Cheers, Neale.>
Re: Florida blue, too much stress?     1/12/13
I should add, I was keeping the 2 inch female Rorschach, 3 inch female Orion, 4 inch Boris, and 4 inch Godfather all in a 10 gallon tank, along with a 3 inch Chinese algae eater male, Bobby, who stands up to the large male crayfish like a large black Spanish bull, also a 1.5" playful yoyo Botia, who strangely befriends everyone and takes turns sharing caves with the crayfish and Bobby, plus 6 zebra danios. Soooo yes, a bit too much for one tank, but everyone lived in peace.
<So far…>
I keep the temp 65F - 75F, have a pump and bubble stones, lots of caves to go around, and do 50% water changes every week. I treat the water weekly with conditioner and Cycle, as well as aquarium salt. Water check hasn't been done in a few weeks, my bad. Iodine I just found out about reading through your website. I now have a 25 gallon beside the 10 gallon making sure there is no overcrowding. I use coral/gravel for the bottom, but do not have live plants. (I am also wondering if it is safe to buy potted indoor thick bamboo, let it root out in the gravel with some waste/food in the aquarium water, and then add it to my aquarium.
<Has been done, yes. But beware "bug sprays" used on houseplants -- these can be lethal to fish.>
I see thick bamboo in closed off small decor aquariums with small fish and African dwarf frogs, the waste keeping the bamboo alive, the bamboo adding necessary nutrients to the water, which keeps the water clean and the critters happy…strange.
<And also unlikely. Bamboo doesn't add anything to the water that's helpful and while plants can remove ammonia from the water, whether they actually "clean" the water is debatable in most aquaria. For that to happen the ratio of plants to fish has to be very high, and the plants have to be growing very fast, by which I mean you're cropping back the plants (i.e., pruning) once a week.>
So back to the bamboo question...safe or not?) The aquarium diet consists of tropical flakes, chopped small fish, brine shrimp, bloodworms, frozen green peas, cucumber, and zucchini to keep everyone happy. Sinking pellets didn't work well since they dissolved too quickly and sunk into the gravel if my crayfish weren't hungry at the time, same with sinking crayfish pellets. I will do water tests, add iodine, sushi Nori asap, but for now my main concern is the wellbeing of Orion with her eggs, lack of appetite, left with only her small claw, suffering great trauma last night. Thank you so much!
<Sylvi, it's time to do some reading. Start here:
http://www.wetwebmedia.com/ca/volume_1/cav1i4/crayfish/crayfish.htm
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/crayfish_basics.htm
Crayfish shouldn't be kept together if you want more than one specimen to do well/survive, and crayfish shouldn't be mixed with fish. Cheers, Neale.>
Re: Florida blue, too much stress?     1/12/13
Thank you for all of the help Neale/crew, and the very quick response!
<Welcome.>
I'm making major changes currently, and I guess I have to give Orion a few days to see if she starts eating, as obviously the stress has been great on her. The reason I kept all my crayfish together was because they were given to me by a friend who has had them in large communities, constantly reproducing for years in a 40 gallon cube tank, along with some tropical fish.
<Ah yes, often happens. And it a big tank, you can get lucky. But crayfish aren't reliably sociable or peaceful, so I'd never recommend them as such.
To be fair, there are one or two exceptions, species of crayfish that seem "better" than others.>
And of course LFS staff are not helpful at all. I heard everything from "peaceful community crayfish" to "two per 10 gallon tank can thrive for up to 20 years".
<I see.>
When reading up on the Florida Blues, that was when I realized I will need a bigger/more tanks to house them all. They seem to have a wolf-pack system though. The largest male was the "Godfather" until the other male Boris took over the role after a battle, which thankfully only resulted in Boris losing an inch of his left antenna, and Godfather having a small piece clipped off of his right claw.
<Sounds about right.>
I wonder if maybe I've been lucky so far which no cannibalism due to the conditions they lived in at my friend's 40 gallon aquarium holding about 40 crays?
<Can be. Overstocking tanks is interesting. While it causes problems in terms of water quality, it does prevent any one fish (or crayfish) getting the chance to establish a territory. Any individual who tries will have to constantly fight all the other crayfish, and he'd never make any progress because all the others are doing the same thing to, and there's no peaceful cave or corner he can defend consistently. Kind of like how when people are on board a crowded subway train the usual rules for personal space are ignored. Anyway, if you have a large group in a reasonably big aquarium with adequate filtration, a sort of status quo is maintained where none of the crayfish becomes dominant. Take five of those crayfish and put them in their own tank and suddenly the rules change. There's now a chance for the strongest specimens to become the boss because he will be able to claim his corner and manage his aggression adequately well, only having to fight the few other crayfish occasionally.>
As for the fish, I added them to the tank in a span of two weeks before the crayfish arrived, with Bobby, the aggressive Chinese Algae Eater protecting his territory, which seemed to work. He stands up for himself and for his new mate, another Chinese about the same size.
<Do read up on Chinese Algae Eaters, which are not from China and don't eat much algae. Properly known as Gyrinocheilus aymonieri if you want to look online about them, they're big fish (20-30 cm/8-12 inches within a year or so) and as adults can be extremely aggressive.>
He also is very protective of Nighthawk, the playful Yoyo Botia, scaring off any of the crayfish that wander too close to their caves.
<I doubt he's actually protecting the loach. They may have common cause at the moment, but long term the chances aren't good they'll get along.
Interesting, the Yoyo Loach (Botia almorhae) is a good community species, and a social one, so you'd be better off keeping 5 of them in a tank upwards of 150 l/30 US gal.>
I have had them in the 10 gallon with the Zebra Danios for about 6 weeks, only having one Zebra killed, and one injured.
<That's actually not a very good track record, one dead fish, one injured fish, and various crayfish injuries.>
So, I think my tank has been installed with some Luck o' the Irish!
<No such thing as luck. At least, look at it the other way. Playing Russian Roulette once and surviving doesn't make it a safe game.>
But now I think I will be safer with 30 gallons for the 5 crayfish, two of which are still adolescent. If I have luck and have hatchlings, I already have a LFS who has a hard time shipping in Florida Electric Blue Crayfish, willing to buy all the surviving hatchlings once they are 3/4" in size. So, I am happy they will have a home to go to.
<Good.>
So, I think I have taken the right steps and am now prepared to keep a safer environment for my tankmates. Last step will be the Iodine on my next stop to the LFS. On a final note, when cleaning the tanks, I do a full hand/arm sterilization as I was required in science/medical labs, and gently usher the crays into my cupped hands to transfer them to the temporary bucket.
<Good personal hygiene/safety when working with aquaria is always a good idea.>
They seem to be fine with this, and I am confident that with the thorough scrub down/wash of my arms and hands, I provide no potential harm or infection to them.
<To be fair, the risk is mostly the other way. Aquaria are commonly infested with things like Salmonella wherever bits of food can decay in warm, moist areas. The only real risk going the other way is if your arms are soapy and that soap gets into the water as that can cause serious harm.
As a general rule, it's also a good idea to clean nets, buckets, etc. or at least let them dry out thoroughly as/when taken from one aquarium to another, as wet objects can carry parasites (like Whitespot) from an infected tank to a clean one.>
Also, I feel that this is a safer transportation method then the net or the pinching in the middle, as this way there is no danger of a struggle ending up in an injury. Does this seem safe enough for the Crayfish?
<Likely so. These animals aren't delicate at all.>
Once again thank you so much for the time and energy you and your staff put into helping out all these hobbyists, and I sincerely apologize for not doing enough research on my part, and for the many badly written and very brief emails and texts you and your crew receive. I can only imagine how irritating this must be on your part. Thank you very much Neale, for all your help and useful information, it is much appreciated! And I hope your weekend goes well, and you have a chance to sit back with friends and enjoy a cold one or two at a nice pub or at home!
<I hope so too! Good luck, Neale.>