crab with eggs
- Thread starter sTefaniA
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BEASTIEPENDENT
Member
Hi Stefania,
this is a Xanthid crab and on the spoony claw tips You can see it is mainly (!) a herbivorous algae eater. They usually do eat whatever they can get so carrion or any food You give it will be welcomed. Normally they don't attack any living being – and it would be not that easy for them since they have no sharp pincers.
The eggs will surely hatch – if they are fertilized but they will normally not grow to young crabs. What hatches are planctonic larvae (called zoea) which have some two to six stages, then a megaopa-stage which looks already like a real small crab and finally the young baby crabs which live benthic of course.
In a normal reef tank the larvae are crushed by flow pumps or filter AND they don't find enough food. Although they are occasional reports that people find new baby shrimp or baby hermit crabs in their tank and these breed in the same way so it is not absolutely impossible You'll find some baby crabs sometime, but it is highly unlikely. Your corals and fish will welcome the larvae - for them they are good food (and that is of course the next point that makes it highly unlikely any larvae will reach the adult stage).
this is a Xanthid crab and on the spoony claw tips You can see it is mainly (!) a herbivorous algae eater. They usually do eat whatever they can get so carrion or any food You give it will be welcomed. Normally they don't attack any living being – and it would be not that easy for them since they have no sharp pincers.
The eggs will surely hatch – if they are fertilized but they will normally not grow to young crabs. What hatches are planctonic larvae (called zoea) which have some two to six stages, then a megaopa-stage which looks already like a real small crab and finally the young baby crabs which live benthic of course.
In a normal reef tank the larvae are crushed by flow pumps or filter AND they don't find enough food. Although they are occasional reports that people find new baby shrimp or baby hermit crabs in their tank and these breed in the same way so it is not absolutely impossible You'll find some baby crabs sometime, but it is highly unlikely. Your corals and fish will welcome the larvae - for them they are good food (and that is of course the next point that makes it highly unlikely any larvae will reach the adult stage).
AJSTITAN14
New member
Haha now those are the kinds of pics you like to have when dealing with crab ID's right Beastie?
much better than "Hi I found a crab in my tank can you tell me what it is? Thx"
much better than "Hi I found a crab in my tank can you tell me what it is? Thx"
LeslieH
Premium Member
Yup, and much better than 90% of the images that show up here. The only thing better would be a straight shot from above of the crab nicely arranged with the legs spread out. Unfortunately most crabs do not watch American's Top Model and don't know the right way to strike a pose.
I agree with Beastie about it being a xanthid, maybe even in the genus Pilodius. The degree of hairiness varies from smooth to quite furry. Take a look at the Pilodius we captured in the northwest hawaiian islands -- http://www.hawaiianatolls.org/research/CoML/features/FFS_True_Crabs.php
I agree with Beastie about it being a xanthid, maybe even in the genus Pilodius. The degree of hairiness varies from smooth to quite furry. Take a look at the Pilodius we captured in the northwest hawaiian islands -- http://www.hawaiianatolls.org/research/CoML/features/FFS_True_Crabs.php
BEASTIEPENDENT
Member
Yes AJSTITAN14, that's much better than many many requests, although not perfect – but Leslie pointed out already the unsatisfying degreee of training in crabs in front of the camera. 
Pilodius might well be. Oh, no, I miss the big round tubercles on the claws which seem to be typical for that genus? Leptodius? No, the eyes are too far lateral here. That should be a Chlorodiella like Chlorodiella cytherea I think.
Leslie: Are You (or Joel Martin) sure, the Polydectus cupulifer on Your linked site http://www.hawaiianatolls.org/research/CoML/features/FFS_True_Crabs.php is really one? For me it does look more like Pilumnus vespertilio. And P. cupulifer shall carry anemones as You stated Yourself in another thread here and linked directly to another picture: http://www.botany.hawaii.edu/basch/uhnpscesu/htms/kalainvr/fish_pops/xanthis/crab05.htm – but this picture is for sure another crab than this: http://www.hawaiianatolls.org/images/coml/crabs/GP-FFS-00178_C_300.jpg – or am I looking wrong? The few other photos one can find from P. cupulifer seems to show a different crab either (carapace and eyes). I don't seem to have the description for Polydectus here, so unfortunately I can't check…
Pilodius might well be. Oh, no, I miss the big round tubercles on the claws which seem to be typical for that genus? Leptodius? No, the eyes are too far lateral here. That should be a Chlorodiella like Chlorodiella cytherea I think.
Leslie: Are You (or Joel Martin) sure, the Polydectus cupulifer on Your linked site http://www.hawaiianatolls.org/research/CoML/features/FFS_True_Crabs.php is really one? For me it does look more like Pilumnus vespertilio. And P. cupulifer shall carry anemones as You stated Yourself in another thread here and linked directly to another picture: http://www.botany.hawaii.edu/basch/uhnpscesu/htms/kalainvr/fish_pops/xanthis/crab05.htm – but this picture is for sure another crab than this: http://www.hawaiianatolls.org/images/coml/crabs/GP-FFS-00178_C_300.jpg – or am I looking wrong? The few other photos one can find from P. cupulifer seems to show a different crab either (carapace and eyes). I don't seem to have the description for Polydectus here, so unfortunately I can't check…
geemanaz
AZ FRAG Club Member
found good site for HAWAII Invertebrates go to http://www.marinelifephotography.com/marine/marine.htm
AJSTITAN14
New member
I'll try and make the pic from above. And I do try my best to make good pics
Yeah it's good work on your part for sure.
I think part of being a crab expert is enjoying the puzzle when you find a new specimin.
LeslieH
Premium Member
We had 3 crab experts on the trip - Jody (Joel), Gustav Paulay, and Scott Godwin. They all agreed it was Polydectus so who am I to disagree? Maybe Jody cleaned the carapace a little too hard when he was prepping it for the camera.
Yeah, Chlorodiella does look like a better choice. Here's another Hawaiian one -
http://www.botany.hawaii.edu/basch/uhnpscesu/htms/kalainvr/fish_pops/xanthis/crab21.htm
Absolutely Ajstitan. I compare it to doing jigsaw puzzles. The characters are the pieces, the literature references are parts of the overall picture, and you have to put them all together in the correct order to get the final ID.
Keep up the good work Stefania. I look forward to seeing more pics!
Maybe Jody cleaned the carapace a little too hard when he was prepping it for the camera.Yeah, Chlorodiella does look like a better choice. Here's another Hawaiian one -
http://www.botany.hawaii.edu/basch/uhnpscesu/htms/kalainvr/fish_pops/xanthis/crab21.htm
Absolutely Ajstitan. I compare it to doing jigsaw puzzles. The characters are the pieces, the literature references are parts of the overall picture, and you have to put them all together in the correct order to get the final ID.
Keep up the good work Stefania. I look forward to seeing more pics!
BEASTIEPENDENT
Member
Oh, damn
Then it's my fault. I have to get the original descriptions for these species"¦
LeslieH
Premium Member
Now those are great photos! Here's a couple of species of Chlorodiella for comparison.
http://calphotos.berkeley.edu/cgi/img_query?enlarge=4444+4444+0907+0268
http://www.flmnh.ufl.edu/reefs/guamimg/crustacea/xanthidae/Pages/Image7.html
http://www.meerwasserwiki.de/w/index.php/Bild:Chlordiella_cytherea.jpg
Beastie - I didn't say they were right. They could have called it a shrimp and I wouldn't have disagreed. 3 crabs against 1 worm are not good odds! :lol:
http://calphotos.berkeley.edu/cgi/img_query?enlarge=4444+4444+0907+0268
http://www.flmnh.ufl.edu/reefs/guamimg/crustacea/xanthidae/Pages/Image7.html
http://www.meerwasserwiki.de/w/index.php/Bild:Chlordiella_cytherea.jpg
Beastie - I didn't say they were right. They could have called it a shrimp and I wouldn't have disagreed. 3 crabs against 1 worm are not good odds! :lol:
BEASTIEPENDENT
Member
Hi Stefania,
sorry, was busy the last days. Tried to ID this crabbie exactly but I can't. I stay with genus Chlorodiella but I can't name the species. It does resemble most closely C. cypreata but it doesn'T match exactly. So its Chlorodiella sp. for now.
If the eggs are fertile You can see when they change color, when you start to see two dark points in them (these are the eyes then) or, of course , when they hatch. Which color fertile eggs have and which unfertile differs from species to species. Some are bright orange, some dark red, others simply grey…
sorry, was busy the last days. Tried to ID this crabbie exactly but I can't. I stay with genus Chlorodiella but I can't name the species. It does resemble most closely C. cypreata but it doesn'T match exactly. So its Chlorodiella sp. for now.
If the eggs are fertile You can see when they change color, when you start to see two dark points in them (these are the eyes then) or, of course
, when they hatch. Which color fertile eggs have and which unfertile differs from species to species. Some are bright orange, some dark red, others simply grey…The eggs have hatched, they changed color yesterday, they went orange with a black spot in it and now I have many tiny swimming plactonic baby crabs.
They are attracted to light and they are sooo small. What do I feed em? I have tons of tiny copepods? I have green, red and microplancton?
They are attracted to light and they are sooo small. What do I feed em? I have tons of tiny copepods? I have green, red and microplancton?
BEASTIEPENDENT
Member
Hi Stefania,
Copepods might work, but here the copepods always sit on the glass and the crab larvae are swimming – so they won't get any of the copepods. Microplancton is alive? Then okay. If is frozen plancton use very small portions since the zoea larvae can only grab it while it sinks and what lands on the substrate will rot there. If it is live plancton – whether zooplancton or phytoplancton – very good. Let the larvae swim in it.
The "usual" way is to breed artemia naupliae. The hatched naupliae are attracted from the light – just as the zoea. So if you feed just shut off the normal light and set a spot in one corner, zoea larvae and their food will gather there. *g*
On our site we have a breeding report for "Red thai crabs": http://www.panzerwelten.de/forum/thread-712.html – these are mangrove crabs but the reproduction with pelagic larvae is quite the same. So You might find some hints there. There are several sites on the internet with breeding reports for marine organisms (including many invertebrates like shrimp, hermits etc. which all have the same principle with zoea and megalopa larvae), but I know only German ones.
One of the most important factors – at least with mangrove crabs – is the temperature, that may not change. 25 degrees Celsius would be the best for the most species, a change about one or two degrees can (!) kill the whole population. Can, not must.
If You're lucky You can count some two to four weeks for the zoea to moult through their two to five zoea stages and one or two megalopal stages up to the tiny young baby crabs. From now maybe 5.000 larvae (no clue how many with this species, may also be a million *g*) some 10 to 100 may get it to young crab (although in breeding Nanosesarma sp. we got more than 300 young crabs in one breeding process, but that's ununsual).
Copepods might work, but here the copepods always sit on the glass and the crab larvae are swimming – so they won't get any of the copepods. Microplancton is alive? Then okay. If is frozen plancton use very small portions since the zoea larvae can only grab it while it sinks and what lands on the substrate will rot there. If it is live plancton – whether zooplancton or phytoplancton – very good. Let the larvae swim in it.
The "usual" way is to breed artemia naupliae. The hatched naupliae are attracted from the light – just as the zoea. So if you feed just shut off the normal light and set a spot in one corner, zoea larvae and their food will gather there. *g*
On our site we have a breeding report for "Red thai crabs": http://www.panzerwelten.de/forum/thread-712.html – these are mangrove crabs but the reproduction with pelagic larvae is quite the same. So You might find some hints there. There are several sites on the internet with breeding reports for marine organisms (including many invertebrates like shrimp, hermits etc. which all have the same principle with zoea and megalopa larvae), but I know only German ones.
One of the most important factors – at least with mangrove crabs – is the temperature, that may not change. 25 degrees Celsius would be the best for the most species, a change about one or two degrees can (!) kill the whole population. Can, not must.
If You're lucky You can count some two to four weeks for the zoea to moult through their two to five zoea stages and one or two megalopal stages up to the tiny young baby crabs. From now maybe 5.000 larvae (no clue how many with this species, may also be a million *g*) some 10 to 100 may get it to young crab (although in breeding Nanosesarma sp. we got more than 300 young crabs in one breeding process, but that's ununsual).
