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FAQs about Marine Crab Feeding

Related Articles: Crabs, Hermit Crabs

Related FAQs: Marine Crabs 1, Marine Crabs 2, Marine Crabs 3Marine Crabs 4, Marine Crab Identification, Crab Behavior, Marine Crab Selection, Marine Crab Compatibility, Marine Crab Systems, Marine Crab Feeding, Marine Crab Reproduction, Marine Crab DiseaseMicro-Crustaceans, Amphipods, Copepods, Mysids, Hermit Crabs, Shrimps, Cleaner Shrimps, Banded Coral Shrimp, Mantis Shrimp, Anemone Eating ShrimpCrustacean Identification, Crustacean Selection, Crustacean Behavior, Crustacean Compatibility, Crustacean Systems, Crustacean Feeding, Crustacean Disease, Crustacean Reproduction,

Trapezia flavopunctata in Hawai'i


Calico Crab refusing food        7/12/15
Hi, first time writing in!
<Ah; welcome>
I recently moved my calico crab (*Hepatus epheliticus*, 4" across the carapace) into a larger tank. Originally she was in a 3 gallon, but the nitrates got out of control fast (the day before the move they were testing off the chart), so I bumped her up to a 25 gallon. The tank is filled with 3 inches of fine aragonite sand
<Mmm; well; the natural habitat of this species is more mud and sand...>
and pre-cycled water from a coral-only tank, and the water levels all check out as optimal as of this morning. She is the only animal in the tank other than a single turbo snail.
Anyway, she's been in this tank for going on five days, and the entire time she's been refusing food. I've tried scallop, shrimp, krill, even a live turbo snail, with no success. When she was in the 3 gallon, she used to burst out of the sand and dance excitedly the moment I put the feeding stick in the water. Now she shoves the food away. Is she just sulking because of the move?
<That and the NO3 exposure... can severely alter physiology... cause blood cells to disrupt...>
I'm concerned she might still be affected by the nitrate spikes in her old tank.
Thanks for any advice you can offer!
<Keep offering some food daily... remove if it's not eaten w/in a half hour or so. Bob Fenner>

Re: Calico Crab refusing food
Thank you for your quick response! I'll keep trying and hopefully she's not too badly addled by the NO3. In the mean time, do you have any recommendations for a muddier substrate?
<Mmm; yes; the various "muds" sold in the trade will do.>
I've never worked with mud in a marine tank and I'm not sure if Miracle Mud is the way to go without any plant life in the tank.
<Indeed it is. Others you can read about on WWM:
(Attached is a photo of her peeping out from under the sand.)
<Ahh! BobF>

Re: Calico Crab refusing food      7/16/15
Just wanted to update you and let you know that after a week-long hunger strike my calico crab is finally eating again. Thank you for your help!
<Yay! Thanks for the update. BobF>

Decorator Crab; Feeding And Compatibility 8/30/09
Okay, so my roomy and I recently set up a 25 gallon salt water aquarium consisting of crushed coral and about 8 lbs of live rock. We decided to throw in a Spider Decorator Crab to entertain us while we
wait for the tank to finish curing and ammonia levels to get as close as possible to zero :) (we made sure they were pretty darn close to nil before adding the crab).
Squeegee, as we named him, seems pretty content, scavenging the tank for whatever he can find on the live rock, not-to-mention the assortment of tropical flakes that we throw in on a day-to-day basis.
This leads me to my first question. Are the flakes enough for the crab to eat and if so how many should I be throwing in there? Also, would feeding the crab ghost shrimp be okay (if so how many a night)?
<Ghost shrimp are fine, maybe one every other day depending on the crab's size. Kind of pricey for crab food.>
And lastly, Is there a more ideal (and cheap?!) sustenance we could be feeding it?
<Flakes are fine and about as cheap as you can get. A few flakes per day should keep him happy. Crabs are opportunistic scavengers and will eat most anything they can find.>
Finally, as far as compatibility goes... the tank was originally intended for a Snowflake Eel (no fish) which we'll be getting as soon as the tank is ready. Do you think a young (6in) Snowflake would attack/devour Squeegee?
<A excellent chance for this to happen as crabs and shrimp are their main diet in nature. Do be aware that your tank will eventually be too small for keeping a Snowflake Moray in good health.>
Would there be any way that we can get them accustomed to each other with adequate feeding long enough so that they can coexist for some extended period of time?
<No. Do read here. http://www.wetwebmedia.com/snowflakemoray.htm>
Thank you!
<You're welcome. James (Salty Dog)>

Striped Urchin Crab Care - 9/15/08 <Hi Tiffany, Lynn here today.> I have a 55 gallon reef aquarium with 60 lbs live rock, sump/refugium, and protein skimmer. I have had it for 10 mos. I purchased a tuxedo urchin with a striped urchin crab (Zebrida adamsii) hosted. <Okay> Unfortunately, the urchin did not make it. <I'm sorry> I thought the crab had perished as well. I had not seen it for a couple of weeks. I saw it during my weekly water change. It was hiding in one of my larger rocks that has a lot of hiding places. It looked healthy and I want to keep it that way. The problem is that I do not know what it eats. <Apparently, this species is parasitic towards its host. It reportedly feeds on bits and pieces of the urchin's tissues and appendages, often leaving bare spots (for reference, see midway down this link: http://www.int-res.com/articles/dao/3/d003p059.pdf). Now that the crab is without a host, I'd offer it any number of meaty foods of marine origin (mysis, bits of shrimp, clam, Silverside, etc). Crabs are generally pretty opportunistic so chances are one/several of these will be fine (along with whatever else it finds on its own within the tank).> Thanks, Tiffany <You're very welcome. Take care, -Lynn>

Re: Halloween Land Crabs…Diet this time - 4/3/08 They are eating feeder fish, crab food pellets and some raw veggies. <<Angie I have to be honest, I do not like this diet at all, particularly the feeder fish. Not only are they relatively void of nutrition but you put your animals at risk to disease every time you offer them. Read here; http://www.wetwebmedia.com/fwsubwebindex/fdgfdrartneale.htm http://www.wetwebmedia.com/goldfshfd.htm The terrestrial vegetables are not a favorite of mine either even for this often terrestrial crab, if you want to offer vegetable matter utilize sushi grade Nori with no flavoring, if you have to go with the "land-veggies" please don't use iceberg lettuce. As for the replacement of the live feeder fish, please utilize meats of a marine origin, and at least once or twice a month soak it in an iodine supplement.>> they live in a 10 gallon tank with several layers of sand deep enough to dig tunnels, a large water dish for soaking and seemed to be very healthy and active. I have had them for about 4 months now and this is the first molting. <<Good luck.>> thanks Angie <<Adam J.>>

Food for a Hawaiian crab? Hey, my parents just came back form their trip to Hawaii and they go a tiny Polynesian crab that lives in his shell. He's cool. Well we don't want him to die, so we put him in a type of bucket with fresh sea water, some corals and sea shells. The thing is we don't know what he eats. << I would try just about any seafood from the supermarket, as well as some algae. >>  So would you please inform me. I was thinking of sea weed but we don't know, << Maybe not the best item to acquire, good luck. >> thanks. <<  Blundell  >>

Sponge Crab Questions (4/16/04)  I have a 1 1/2 inch sponge crab that I am keeping in a 20L aquarium right now with a few fish..... I call him "Sponge Bob." Bob is a cute little fellow but I know very little about his dietary requirements. He is eating small pieces of silver side right now. What else would give him a good balanced diet? I assume, like most crabs he is not reef safe, right? <Exceedingly unsafe and very destructive.> I would love to put him in my Harlequin Shrimp tank ( it has a few limpets too) but fear he might hurt them, would he? <Quoting Calfo & Fenner, they "have no place with a casual marine aquarist or in mixed invertebrate reef aquariums.> He lost his sponge and is currently carrying around a small piece of green 3M Brillo pad on his back........I call him "Brillo Bob," now:) Thanks for the help! Janey <These crabs do tend to be omnivorous with a leaning toward meaty foods. I had a hard time finding much info. I'd suggest you search the terms "sponge crab" and "Dromid" on WWM & Google to get more info. Steve Allen.>

Crabs and shrimp not eating - 3/16/04 About 10 days ago, my inverts except for 3 snails started acting funny. <OK>  They have become exceptionally listless. <Strange>  I have 1 skunk cleaner shrimp, 1 blood shrimp and 9 small hermit crabs.  I also have 1 turbo snail, 1 bumblebee snail and 1 narcissus snail.  The only fish are 1 percula clown and 1 coral beauty. <OK> The snails and the fish seem perfectly fine, but the shrimp and crabs don't seem to move as much anymore. <Change foods?> The only thing I have done differently was upgrade the light to a 10,000K 65W Custom SeaLife Retrofit kit. <From what? Most of the shrimp and crabs tend to be a bit more active at night (dusk and dawn) for safety>  The tank is a 29g, with Aragonite substrate.  The local fish store said maybe a electric current is going on, so I bought a titanium ground probe.  Did nothing. <Not necessarily but likely not the problem. I would keep the probe though> They do move around at night however. <Try different foods, but night activity is a little more "realistic" to their natural state> I have had each one for over a month now and up until 10 days ago, they were all active and doing fine. <Lighting change (intensity) likely scared them into a more realistic reef state. Also try different foods catered to their needs.> They used to be ravenous eaters, now I haven't seen them eat at all. <Food change and try feeding a bit at night after lights out> Maybe they eat at night. <Possible. If you are not target feeding them then maybe they have nothing left to eat?>  My param.s are SG 1.022, temp 80, ammonia 0, nitrite 0, nitrate 15 ppm. <All fine as far as that goes. Could be other parameters out of normalcy> Have started doing top-offs with RO water <freshwater top off no saltwater mixed, right?> and am about to do a 5 gallon water change with RO water. <R/O with sea salt mixed in right?> What could be the problem? <detailed throughout the email> I did a 5 gallon water change a few hours before this appeared, but I had done a 7 gallon water change a week before.  Thanks. <Thanks for being part of it all ~Paul>

Crabs and shrimp not eating - 3/16/04 The snails and the fish seem perfectly fine, but the shrimp and crabs don't seem to move as much anymore. <Change foods?> Nope. <Don't be so sure> Alternate between Reef Plus frozen and an Angel Mix frozen, feeding every third day.  They would eat anything, especially the Reef Plus since it seemed to clump more and they could grab and hold on better. <Well, not sure what else to tell you. Let me know after the water change how things go. Maybe they are preparing to molt or have just molted> The only thing I have done differently was upgrade the light to a 10,000K 65W Custom SeaLife Retrofit kit. <From what? Most of the shrimp and crabs tend to be a bit more active at night (dusk and dawn) for safety> From a standard 30 inch bulb that came with the tank originally from Wal-Mart. <Needed the upgrade> I understand about being more active at night, but this malady (if you can call it that) started at about noon, and 3 days after I upgraded the lighting. <Noon today? Either way they could be adjusting. Again, there may be something else going on. Nothing rings a bell though.> <Not necessarily but likely not the problem. I would keep the probe though> I thought that was odd, but still have it anyway. The only electrical appliance in the tank is the heater, and only the glass is in the water. Glass is an insulator. The other issue could be from the new light, but the connections are capped and their is a layer of glass between the hood and the water in the tank top, again insulating from stray current or spikes. <Not likely electricity> <Try different foods, but night activity is a little more "realistic" to their natural state> How long can they last without eating? <Not very long. Maybe a week or so> It's been almost 10 days since I've seen them eat. <Likely eating when you are not looking. This is understandable as they "go to town" initially and once food source is under control, they sort of slow down and graze>  And what would be a good food for them? <Try the sea veggies product. Strips of Nori seaweed or something of that sort. Spirulina cubes or sinking pellets>  I know if I just put food in the tank, the angel and the clown will eat it. <True. Feed them first. Then why they are busy try feeding the others> I've seen the angel take food from a crab before. And how can I target the shrimp specifically?  Hand feeding?  I try not to put my hands in unless I need to. <Use a feeding apparatus or feeding tongs> <Lighting change (intensity) likely scared them into a more realistic reef state. Also try different foods catered to their needs.> See above.   <Possible. If you are not target feeding them then maybe they have nothing left to eat?> Also, having a bit of a bout with brown algae, diatoms? <Hmmmm> That didn't start until about a day after they first showed this behavior. <Strange> Could that be a problem? <Might be related but I don't think algae showing up in itself is an issue here> From what I have read in a book I have, on forums on the Internet and from the fish store, this is good, but the only creature that will eat diatoms are tangs, <Not necessarily. Read through our FAQs and articles on algae control.> and my tank is too small. <Yes> Maybe if I could find a juvenile one, and trade him in when he gets bigger perhaps? <I wouldn't. Is this tank newly set up?> <All fine as far as that goes. Could be other> parameters out of normalcy> Those are all I can test for now. <Fine> <freshwater top off no saltwater mixed, right?> Right <Whew. Glad to hear. I thought otherwise but had to ask> <R/O with sea salt mixed in right?> Right.  Have an airstone in there now, SG is 1.022, same as tank, and before I actually remove water from tank, will bring temp 80 which is the same as the tank. All param.s tested fine too...oh, and my pH is 8.3. <Excellent, excellent, and excellent> Thank you so much for the prompt reply.  I wish I had found this site before now...oh well, I'm here now.  :)  Any other ideas?  Thanks again. John Gainesville FL

- What do Anemone Crabs Eat? - Evening Gents! <Good morning.> I recently purchased a "anemone" crab from my LFS.  It looks very much like the one pictured on crabs 3 page top photograph "Neopetrolisthes maculata".  He has moved in to my Bubble tipped anemone, however, he does not appear to want to eat chopped foods provided (Mysis shrimp, table shrimp, silversides).  Do you know what kind of foods these types of crabs eat? <I'm not 100% certain, but it's my understanding that these crabs and also the ones that live in/among Acropora derive most of their nutrition from the mucus secreted by the animal they live on. The mucus traps very small particles that provide a food source for the crabs.> He has long thin claws and I wonder if he scavenges from the anemone. <Sort of...> I have another crab I call him sweeps (different tank) and he willingly accepts chopped foods. <Many do.> I read all the FAQs about crabs and crab ID and don't see anything about this type.  Please help me if you know. Thanks again - I rely a lot on the info provided on your site.  I tried the Google search - with no luck.   Tammie <Cheers, J -- >

Re: more feeding <<JasonC here...>> I also got a Blue Boxer Crab, I could not find much Information about them. Any ideas what they eat. <<just about anything they run into, or that runs into them...>> My LFS said brine shrimp <<that would work. Cheers, J -- >>

WHAT TO FEED A DECORATOR CRAB... I BOUGHT A DECORATOR CRAB TWO WEEKS AGO AND HAVE JUST BEEN LETTING HIM FEED ON HIS OWN. I CAN NOT FIND ANY INFORMATION ON THEM THAT TELLS OF THERE DIETARY HABITS. HE IS IN A FISH ONLY TANK, DOES HE NEED LIVE ROCK TO USE FOR HIMSELF AND WILL HE EAT BROWN ALGAE. >> These animals are feeders on other invertebrates: worms, shrimp and other crustaceans... and a minimal amount of greenery... They can live pretty well on newer live rock inhabitants, in addition to meaty scraps from feeding your fishes and other invertebrates. Bob Fenner

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