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FAQs about Horseshoe Crabs, Disease
Related FAQs: Horseshoe Crabs 1, Horseshoe
Crabs 2, & FAQs on: Horseshoe Crab ID,
Horseshoe Crab Behavior, Horseshoe Crab
Compatibility, Horseshoe Crab Selection,
Horseshoe Crab Systems, Horseshoe Crab
Feeding, Horseshoe Crab Reproduction,
& Crustaceans 1,
Micro-Crustaceans, Amphipods,
Copepods, Mysids,
Hermit Crabs,
Shrimps,
Cleaner Shrimps,
Banded Coral Shrimp,
Mantis Shrimp,
Anemone Eating Shrimp, Related
Articles: Horseshoe Crabs: Latter Day
Trilobites for Some Systems &
Crustaceans, Micro-Crustaceans,
Amphipods, Copepods,
Mysids, Isopods,
Shrimps,
Coral Banded Shrimp,
Cleaner Shrimp, P. holthuisi Pix,
Mantis "Shrimp",
Lobsters,
Slipper Lobsters,
Hermit Crabs, Squat Lobsters,
Crabs,
Arthropods, Pycnogonids (Sea Spiders), | 
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Limulus polyphemus questions – 08/26/09
We have had six horseshoe crabs (Limulus polyphemus) for the past 6
years for our touch tank- two are out for touching, and the other four
are held and rotated periodically.
Our largest one (shell is approximately 6 inches across) molted 2 years
ago, but the new shell has never reached the normal level of hardness.
It seems to be thinner and gives to the touch. Calcium levels in the
tank are in the 330 to 360 range. Any ideas on why it has not hardened
up?
<Mmm, yes. Best guess is a disproportionality of Magnesium (should be
about 3X Ca) and/or low Alkalinity... in the water, though these can be
made up in foods>
Our other issue is on another crab in our holding tank has just recently
developed loss of color and hardness in portions of the last half of its
telson, with the last 2 cm breaking off. Anyone out there have any
experience with this sort of problem?
<Mmmm.. is there an excess of nitrogenous wastes, e.g. Nitrate present?>
The crabs are fed either mussels or silversides. Tanks are kept around
14 C degrees, specific gravity 1.020,
<Too low... this may be a factor... I'd raise to 1.025>
Ammonia <.15, Nitrite .02,
<These should be 0.0 ppm>
Nitrate 0, Mg 1290, pH 8.4, Alkalinity 3.6. with algal scrubbers for
filtration.
<Likely NO3 issue with this form of filtering>
Thanks for any ideas.
Dave Sobal
CSC Aquaria & Animals
<... Catawba... Bob Fenner>
Horseshoe Crab/Health 2/9/07
I'm hoping you can help me out.
<Hope so, Deborah>
I have a 90 gallon well-established salt tank
that currently houses five yellow-tail damsels, a striped damsel,
and a horseshoe crab. We have had the damsels for almost two years
and the horseshoe crab for almost a year now. We were lucky enough
to watch our horseshoe crab molt and got to save the shell (see
attachments). We are currently fixing a poisonous algae problem and
I think it has affected the horseshoe crab. I found her upside down
under one of the filters this morning and thought she was
dead. When I netted her and brought her to the surface, her gills
were moving but very slowly. I put her in an isolation/hatching net
(see attachments) and saw that she improved quickly. Her tail is
snapped at the end which I realize she will likely regenerate during
her next molt. Finally, I am getting to the point of my letter. I
don't want to release her until this evening when the bulk of the
algae is cleaned but, she has other plans. In her attempts to free
herself from the isolation box, she keeps landing on her back and
can't right herself because of the snap in her tail. I have spent
the better part of the morning flipping her back over. Do you think
it's safe to release her? How long can she stay on her back
safely? Thanks so much, in advance, for any help you can provide.
<I'd leave the crab in isolation until health improves, eating,
righting itself. Having gravel in the isolation tank will help it
right itself. If you have treated the tank with an algae inhibitor,
this very well could have affected the crab's health.
Read FAQ's
here and linked files above. Learn here from the experiences of
other Horseshoe Crab keepers.
http://www.wetwebmedia.com/horseshoecrabfaqs.htm James (Salty
Dog)>
Deborah |  |
Re: Horseshoe Crab/Health 2/9/07
Thanks so much for sending
such a fast response.
<You're welcome.>
It's nice to know
that there are volunteers taking the time to help those of us who
need it especially when the same LFS who sell these little guys know
nothing about them. I ended up releasing the crab late last night
because the tank bottom was cleaned. A few months ago we found that
our substrate was too thick resulting in not enough aeration and it
was causing spots of anaerobic bacteria throughout the tank.
<Yes, can/will happen.>
We removed a lot of the substrate and
the problem slowly subsided. Harry (the horseshoe crab)
<Skinhead would have been a better name:)>
also helped with that
because she constantly moved the substrate. Recently, the same
bacteria came back with a vengeance and we were concerned that Harry
would be affected. We were told by our LFS that we should replace
our lights. I have been telling my husband this for months. Now,
its just a waiting game. Harry seems to be holding her own but
insists on staying directly beneath one of our filters. As for your
response to
my original email, we don't use algae inhibitors
because normally our tank produces just enough of the good algae to
keep our fish happy.
<My concern here is the chemical make-up of
some of these products that can affect the health of invertebrates.>
I wish I could have put gravel in the isolation tank. It would have
kept me from spending the day flipping Harry over. Its a net tank
and just can't handle the extra weight of any gravel. I've decided
to use my spare 10-gallon tank for all future isolation
issues. You're horseshoe crab FAQ's section has been a
lifesaver. We bought Harry on a whim, like so many others
mistakenly do (our first unresearched purchase) along with a hermit
crab from our LFS. We knew nothing and could find no information
anywhere. We even went to two large local aquariums and they could
not help us. After many more long hours searching online, we
finally found your website! What a relief we felt. Your site has
been a constant source of valuable information for to us. This
reply needs no response. Thanks for all that you do for us.
<You're welcome, Deborah, and continue reading/learning. James
(Salty Dog)>
Deborah Rowe |
Horseshoe Crab
Health and Cucumber Fission 4/5/07
Hello! <Hi Susan!> I just
recently found your site and have learned a great deal from it already.
<Thank you! How may we help you today?>. I have a 30 gallon tank that I
have had for about 4 years. I purchased a horseshoe crab, sadly, since I
have read your article, 3 years ago. <Wow, considering their specialized
needs, 3 yrs in a 30g tank is a long time for one of these guys to
survive!> He has seemed to do well until the past week, he has molted
twice
during the time I have had him. <Depending on his age, he
should have molted more than this over a three year period> He now has a
dark brown color to his back, his shell is soft and he does not seem to
be moving his gills very often.<Did he just molt in the last day? If so,
that would be normal. Their shell doesn’t harden for around 24 hrs. If
not, that combined with the slow gill action sounds like he’s in
trouble. How is everything else in the tank? What are your water
parameters, including calcium? Have you ever tested for Iodine/Iodide?
Is he still eating and if so, what do you feed him? Also, how large is
he now?> He also is spending a lot of time upside down.<Horseshoe crabs
sometimes do odd things but all in all, I’m concerned for the little
guy> I do hope I have not starved him or caused him other harm. <If he
survives, he really needs to be in a tank more equipped for his needs.
Please read the FAQ listed as “Horseshoe crab Overview 4/14/03” at this
link:
http://www.wetwebmedia.com/horseshoecrabfaqs.htm > It is a shame
that some fish dealers do not have the knowledge to help educate people
on purchases. <Agreed. Horseshoe crabs are wonderfully interesting
creatures that in the right setting, can be very hardy. Unfortunately,
they’re not well suited to the warmer, predominantly rock filled reef
tanks that most saltwater enthusiasts keep> I will not make another
purchase without checking your site first. <Yes, it’s a difficult lesson
that many of us have learned the hard way, but the good news is that by
you writing this, you may be saving another life down the road> I also
have a light spotted sea cucumber that recently divided into two sea
cucumbers. Both "halves" seem to be doing fine but I have not been able
to find any information on this. I would appreciate any help you could
give me. <Ha! Thought you were seeing double, didn't you? Actually,
"fission", or splitting into two parts in this case, is normal for some
species of cucumber. Interestingly enough, these species can reproduce
sexually or asexually. What usually happens is the cuke will disappear
for a bit, maybe a week or two, then reappear as two separate entities!
How neat is that? Here’s a link to our Faq’s on cuke reproduction:
http://www.wetwebmedia.com/cukereprofaqs.htm > Thank you for your
time and expertise.<You’re very welcome, Susan! -Lynn>
Small SW... Horseshoe Crab... No useful info. – 06/08/07
Hello,
I just recently found your site and have learned a great deal
from it already. It is a shame that some fish dealers don't have the
knowledge to advise people in their purchases in the beginning.
<Such is the nature of experience, reality... "Once you get something
wired... your chances are generally long over">
I have a 30 gal tank,
have had it for 4 years. I purchased a horseshoe crab
<What species?
Might be at the end of its lifespan for these circumstances...>
three
years ago. (sadly, after reading your article). It has seemed to do well
until the past week. It has molted twice in the time I have had him. He
now seems to be in trouble, hopefully I am not starving him, but he is
spending a lot of time upside down, his gills do not seem to be moving
very often and his shell is soft and has a brown tint on the back that
was not previously there. Any help would be greatly appreciated.
<Mmm...>
I also have a light spotted sea cucumber that I have had for
about a year.
<Could be a factor here as well...>
It recently
divided into two separated cucumbers. Both "ends" seem to be doing well
but I have not been able to find any information on this.
<Need to
identify... Pix?>
Thank you again for your time and expertise. I will
definitely see your page before any future purchases.
<Uhh... need
more input... system make-up, maintenance, water quality tests/history,
foods/feeding... Bob Fenner>
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