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FAQs on Freshwater (and Terrestrial) Crustaceans, Health 

Related Articles: Freshwater CrustaceansInvertebrates for Freshwater Aquariums by Neale Monks, Forget Crawfish Pie, Let's Make a Crawfish Tank! By Gage Harford

Related FAQs:  FW Crustaceans 1FW Crustaceans 2, FW Crustaceans 3, FW Crustaceans 4, & & FAQs on: FW Crustacean Identification, FW Crustacean Behavior, FW Crustacean Compatibility, FW Crustacean Selection, FW Crustacean Systems, FW Crustacean Feeding, FW Crustacean Reproduction & Crustacean Selection, Crustacean Behavior, Crustacean Compatibility, Crustacean Systems, Crustacean Feeding, Crustacean Disease, Crustacean Reproduction, Freshwater Shrimp, FW Crabs, Terrestrial Hermit Crabs, & Marine Hermit ID, Hermit Behavior, Hermit Compatibility, Hermit Selection, Hermit Systems, Hermit Feeding, Hermit Reproduction, Hermit Disease/Health, & Crayfish FAQs, Crayfish 2, Crayfish ID, Crayfish Behavior, Crayfish Compatibility, Crayfish Selection, Crayfish Systems, Crayfish Feeding, Crayfish Disease, Crayfish Reproduction,


Blue crayfish injury      6/14/17
Hi there, I have a blue crayfish and whilst moving it from the tank for cleaning (I scooped it up in its terracotta cave ) I tried to pick it up... it jumped. ..! I jumped.., dropped the pot and banged it's head!
The injury is about 4weeks old. Is this injury likely to kill it? It looks no worse after these weeks.
<That the animal has survived this long is a good indication that it will persist; and clear this crack with the next moult or two.
You do administer Iodide regularly? I'll list the reading: http://www.wetwebmedia.com/fwsubwebindex/crayfishdisfaq.htm
Bob Fenner>

Re: Blue crayfish injury     6/14/17
Yes, marine iodine, half dose as specified in your previous q&a's. Will it moult again though?
<Yes; if it lives>
It's approximately 3yrs old, I didn't expect it to get any bigger, though I'd be delighted if it did.
<Moulting frequency decreases with age/size, but never stops altogether>
Does the head area moult too?
Is the discoloured fur on its pincers normal or should I attempt to remove it?
<Looks like algae of some sort... this will come off w/ the moult>
Thanks for your swift response
<Welcome. Bob Fenner>

Please help. Wood shrimp med. poisoned         8/24/16
Please help me i have a wood shrimp in my tank along with other fish the glow fish had ich i used ick away with the wood shrimp in the tank during medication for three days but used only half the dose which was three drops in a ten gallon tank today i saw the shrimp upside down not moving along the bottom on the rocks its still a little alive we moved the wood shrimp into a separate place with new water and a air pump and a hiding rock its still alive but wont move much sitting on the rock cave hands are black and tucked in is it gonna make it and live and is there anything i can do for it please help asap thanks
<Just keep it under propitious conditions. Bob Fenner>

The Plague! (Maybe). FW snail control, crustaceans...      12/5/11
Hello. I just noticed a problem with my aquarium... I have quite an odd aquarium you see! Its one of those.. Nano Cubes.. but its the largest Nano Cube! (Which still isn't very big) And inside of this I have 3 main species: Crayfish, Snails (Invaded), and some form of miniature lily pad (Invaded). What I mean by "(invaded)" is when I bought some of these crayfish, or plants, a little creature came with them! First time it was just one snail.. one snail, not too much! Right?.. Wrong.  I think they reproduce asexually or something because I had maybe 50-60 of them! They are all really small though, their max size is about the size of a piece of rice.
<Unless these bug you aesthetically, they're not a problem>
At one point every morning I killed a couple with this window-scrubber thing you use to get the algae off of your glass. I had to do these to keep them in check! But now.. they are all gone! Not that I liked them much in the first place, but it is quite odd to have an epidemic one day and have it disappear several days later.
<Mmm, not really. Likely the Crayfish discovered how edible they are>
 (My aquarium is in pretty good health since I have plenty of Crayfish who have lived quite long seemingly without problems) Now.. with the Lily pad infection. One day I bought some plants and wouldn't you know it some Lily pads came with them! Also about the size of a piece of rice. But I think these things have minds of their own... sometimes I see them with these thin string projectiles attached to the sides of my aquarium of the filterer. And I KNOW they reproduce asexually since their plants.. Its impossible to eradicate them since if one is hiding somewhere they come back. They clog up my filterer and block out the light from my light bulb that is giving my crayfish.. light. But one day.. nearly around the same time frame as the snails they all disappeared! (Almost) And I was quite pleased. Better yet they weren't even coming back. Around this exact same time I was experiencing a flourish in life from my Aquarium. None of my crayfish were dying, and everything was fine and dandy. I decided to get this one big crayfish to accompany my Dwarf Crayfish.
<... these are largely predaceous species... Eat one another>
 (Who are about the size of two-three pieces of rice!) This crayfish was about 2-2.5 inches long. Quite a big fella but I was told he did not harm any small crayfish and all he did was clean the ground, eating the particles he finds. And it was good.. for about 2-3 months. Then a serious of cataclysmic events happened! First my crab (also small, maybe one inch) who I had for about 8 months died! Soon after that period the 'invaders' started coming back. Then about 4 days ago I saw my big crayfish, who is usually always in hiding be outside.. directly in my view against the glass. I guess he wanted to get out of his dark hiding? I was wrong! He didn't move from that point. He was still alive since he was moving his hands around and pointing his antenna in certain directions. Then his body started changing color... his head (carapace area) was turning red!
Now I knew something had to be wrong, he must have a disease!
<Not necessarily, no>
Now as of about yesterday evening I noticed his tail has started to turn red, I looked up on Google if there were any diseases that matched this description but I could find none.
<Likely just change due to age, maturation...>
Now the center of his body is turning yellow and I assume it will be red soon. I have not changed any procedures I do in keeping my aquarium healthy! I did the same thing ever since I got my aquarium and everything has been fine, no diseases, no nothing. But only as of recently have bad things been happening... what should I do?
<Mmm, keep on keeping on...>
 Should I completely clean out my aquarium and fish out the remaining crayfish until then? Get a new filterer? Use some kind of disease-killing liquid?
<I wouldn't, no and nah>
I would get one, but I don't even know what disease this is! Is the return of the invaders linked to the death of the crab?
<At least temporally eh?>
Was he keeping them in control somehow? Is the death of the large crayfish linked to the return of the invaders!? Thanks for your help!
<Please read here re Snail control:
and the linked files above. I wouldn't change anything in this system overtly. Bob Fenner>

Cherax quadricarinatus - Red Claw Crayfish/"Lobster", Molting Issues Hi I have a red claw lobster and it is laying on its side and it is still moving and it looks like it is molting because some of the shell is off. I was wondering if it is molting or is it dying. <Tough to say, I'm afraid.  Laying on his side is not a good sign, I must say.  It does sound like he's having difficulties with molting, a "bad molt", as it were.  At this point, the best you can do is wait and see.  In the future, though, please consider adding iodine to his tank, to help him with his molts in the future.  I use Kent Marine iodine (marketed for saltwater tanks) at a rate of one drop per ten gallons every week.  The difference this tiny bit of iodine makes is truly amazing.  Since using iodine in my freshwater shrimp tanks, I haven't lost a shrimp to a "bad molt".  For now, just leave him in peace, and hope he recovers.  If he does, do please start dosing iodine in his tank to prevent this from happening again; if he doesn't, well, at least you know you can prevent it from happening to future pet crayfish.  My fingers are crossed for your crustacean pal.> Can you e-mail me back at XXXX please. <Done.  Wishing you well,  -Sabrina>

Cherax quadricarinatus - Red Claw Crayfish/"Lobster", Molting Issues, II (01/31/2004) I am sorry for e-mailing you back here it's just I don't know what XXXX means. <Since we post these questions and answers for all our readers to read, and you had posted your email in the text of the message, I removed it; that's all the X's were for.  While on this note, though, the text sent back with this reply was very, very jumbled; I hope that it made it through to you okay.> My lobster has been laying on it's side for 3 days and only a little bit of it's shell is off. It looks like he is trying really hard to get the rest of the shell off. What should I do? <If there are any other animals in the tank with him, it'd be a good idea to quarantine him separately to help him recover.  Then I would certainly add iodine (I use Kent marine iodine at a rate of one drop per ten gallons) to his tank; this might help him out.  Further, you should definitely check your water parameters (ammonia, nitrite, nitrate, and pH), and ensure that ammonia and nitrite are zero, and that nitrate is as low as possible.  If not, do water changes to correct the issue.  Any of these values being too seriously out of whack could cause harm to your crayfish.  Wishing you well,  -Sabrina>

Attack of the Killer Cabomba? - 08/22/2004 My sister put a plant called Cabomba caroliniana in her aquarium and within hours the shrimps she had died. <Pure coincidence, unless the plants had some sort of toxin spread on them....> Does anyone know if this type of plant is injurious to shrimps? <It is not, not at all.  I have had plenty of shrimp in aquaria containing this species of plant.  Did your sister use any sort of a dip for the plants before adding them?  Some people will dip plants in solutions to kill snails, etc., and if not rinsed *thoroughly*, I imagine some of the water from the dip would get in the tank, and possibly cause harm.  Otherwise, I assume this is pure coincidence.  If you wish to explore other reasons for the shrimps' deaths, please respond with great detail on your tank - what size tank?  How many and what kind of shrimp?  How many and what kind of fish?  What do you feed the animals?  How often do you change water?  What other maintenance do you do?  Do you add any chemicals to the water (aquarium plant fertilizers, iodine for the shrimp, etc.)?  What are your readings for ammonia, nitrite, nitrate, and pH?  When was the most recent animal added to the tank, and what was it?  Hoping to help you get to the bottom of this,  -Sabrina>

Freshwater shrimp? Dear Crew, We have unfortunately had a small tragedy in our freshwater tank (240L, ph6.5-7, temp 75-77, nitrates 0, hardness 3-4)...in with our neon tetras (11), black widow tetras (6), Otos (5), Rams (3), Corys (6) we had had 5 "red claw shrimp". Now from the pictures on your site and on all of the other freshwater shrimp sites, they look like ghost shrimp, but are a reddish/orange color. We bought them from one of the LFS staff who lives in our area and breeds them in her tank. The biggest of these fellows is about 2 inches long, and the smallest about 1 inch. Until yesterday all was well (how can you tell there's going to be a but) but yesterday evening I noticed small red shrimp on its back, scrabbling a bit. I thought this was strange, so turned him over and moved him into a sheltered corner, he seemed to be struggling, so I wondered whether he was molting and turned off the tank lights to minimize stress and left him to it. This morning at work I have received an e-mail from home telling me that small red shrimp is no more. So now I have 2 questions, first of all, do you have any ideas what species these fellows might be? and secondly, what could have killed small red? his legs and claws looked strangely pale and he seemed sort of bunched up (cramp?) but apart from that we have no clue... Any suggestions would be useful, we want to prevent the same happening to the other 4. Thanks for your time. Nicola <Hey Nicola, sorry to hear about your shrimp. It is hard to get a positive ID without a good picture. The common ghost shrimp will not reach 2in. Take a look at the link below, is it one of these guys? http://www.calacademy.org/research/izg/SFBay2K/ghostshrimp.htm My first concern would be water quality. I would do a good water change, and add a poly filter to absorb metals and many other contaminants. Keep an eye on the other shrimp, if it starts happening to the others we will know that it was not a molting complication and can start troubleshooting from there. Let us know how it goes, Best of Luck, Gage.> Nicola Blay, BSc, MSc International Zoo Veterinary Group

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