# Rainbow crabs



## gambite (Apr 12, 2009)

Anyone else ever have any of these? I think they are really awesome. I got two for $15. Any tips on care? I have them with a few inches of sand/coco fiber, a dish of fish pellets for food with dusting of calcium, and a medium sized water dish with plans to get a much larger one that should take up 1/3 of the tank space. The tank is fairly low and flat, with a bit more floor space than your standard 10g.


----------



## davidbarber1 (Apr 12, 2009)

Those are WAY to cool! I've always wanted to get some kind of terrestrial crab. I will have to look those up. Thanks for the pics.

David


----------



## claymore (Apr 14, 2009)

Those are not Rainbow crabs. They are most commonly known as Moon Crabs or Halloween Crabs. I have 2 of these.

They are Really great crabs!

They like to burrow and need at least 6 inches of substrate to burrow.

I use a 75% sand and 25% coco fiber mix. And make sure the substrate stays moist to sustain their burrows.

And for food I give them a nice mix of greens (collard,spinach,turnip,ect..),fruit (apples,bannanas, and pears),also I give randome food like bird seed, brine shrimp, and dead crickets. They are scavengers in the wild. They're main diet consists of leaf litter washed up by the waters edge and what ever they find in the scrub of the forest.

Also it is good to offer a salt water source. I also was told to stay away from comercial hermit crab food.

Here is a link from my original post...   http://www.arachnoboards.com/ab/showthread.php?t=146585&highlight=halloween+crabs


Other wise nice crabs!! I love mine and I hope you love yours too! Enjoy


----------



## xenesthis (Apr 14, 2009)

*Moon Crabs*

See: www.flickr.com/photos/14734284@N02/sets/72157613576321634/

<edit>


----------



## RoachGirlRen (Apr 15, 2009)

Definitely follow claymore's link, _lots_ of good info & discussion in there. He pretty much has it covered, but I'd just like to add that if you can get pesticide-free naturally fallen oak leaves, they go CRAZY for it. Stick to mostly fresh foods; greens, sprouts, fruits, as suggested. The occasional thawed silverside puts them on cloud nine.


----------



## LeilaNami (Apr 15, 2009)

claymore said:


> Those are not Rainbow crabs. They are most commonly known as Moon Crabs or Halloween Crabs. I have 2 of these.
> 
> They are Really great crabs!
> 
> ...


I think this is just another reason why common names suck :}  Probably were listed as Rainbow crabs as well where OP saw them.


----------



## claymore (Apr 15, 2009)

RoachGirlRen said:


> Definitely follow claymore's link, _lots_ of good info & discussion in there. He pretty much has it covered, but I'd just like to add that if you can get pesticide-free naturally fallen oak leaves, they go CRAZY for it. Stick to mostly fresh foods; greens, sprouts, fruits, as suggested. The occasional thawed silverside puts them on cloud nine.


Thanks Ren!  I'll have to try the oak leaves. Do you think I should do fresh or brown and dry?

And whats Silverside???

Have you decided to get some of these yet???


----------



## gambite (Apr 16, 2009)

I think silversides are a type of fish. At the moment, I have fish pellets in there for them. It has become clear that they like to burrow, so I will need a deeper tank than I thought. And the dealer did not have them labeled at all; I had seen rainbow crabs for sale in the past, and they kinda resembled some of the pics I found of them online. These guys need saltwater? How much? At the moment, I have them on a mix of coco fiber and sand, and I gave them a small, sloped paint-tray filled with water. I am thinking about getting some more of them (they are cheap), and spraying them with texture paint and maybe some enamel. 

Can two of these live together? The tank I have them in ATM is wide and flat, the generic equivalent of the last one pictured here (with two openings at the top):
http://www.exo-terra.com/en/products/faunarium.php

And I do have a male/female pair, so does anyone have any ideas on how to induce breeding?


----------



## blazetown (Apr 16, 2009)

Yeah I have this color morph or whatever it is of the moon crab. I want to get some of the black and purple morphs to add in with mine. They block themselves underground in burrows for a long time occasionally.


----------



## claymore (Apr 16, 2009)

gambite said:


> I think silversides are a type of fish. At the moment, I have fish pellets in there for them. It has become clear that they like to burrow, so I will need a deeper tank than I thought. And the dealer did not have them labeled at all; I had seen rainbow crabs for sale in the past, and they kinda resembled some of the pics I found of them online. These guys need saltwater? How much? At the moment, I have them on a mix of coco fiber and sand, and I gave them a small, sloped paint-tray filled with water. I am thinking about getting some more of them (they are cheap), and spraying them with texture paint and maybe some enamel.
> 
> Can two of these live together? The tank I have them in ATM is wide and flat, the generic equivalent of the last one pictured here (with two openings at the top):
> http://www.exo-terra.com/en/products/faunarium.php
> ...


Yes you can have more than one in the same enclosure. Crabs are known to do better in numbers than singly. Just Make sure that you have only one Male. I don't know about this species but Fiddler crab Males fight and are territorial.

I would up grade to a bigger tank! I started out with a ten gallon and quickly moved them into a 20 long! Now I'm debating if I should upgrade them to a 29 gallon for the height. So I can give them even deeper Substrate!

I Give mine a semi shallow dish of salt water. It seems they use the salt water to clean their gills. But I have a decent sized water section with fresh declorinated water with a filter. My Crabs seem to be more active with the sound of running water in their enclosure, Or so it seems. These guys like to climb to! So if you can switch to a 29 gallon right away that would give you the option to give them some rocks and plants to climb on!



gambite said:


> I am thinking about getting some more of them (they are cheap), and spraying them with texture paint and maybe some enamel.


:?    

To breed these guys is very difficult. First off you need a large salt water source to simulate the sea, and a wave simulator. Second you would have to create a lunar cycle to induce breeding, maybe even a hibernation cycle.
Third the young hatch from the eggs and spend quit a bit of time as plankton and only emerge out of the water after several molts as crabs.

It's pretty dificulte to breed these guys. No one has in capitivty as of yet at least. Thats why they show up as imports.

Hope this helps!


Clay


----------



## Cocoa-Jin (Apr 16, 2009)

claymore said:


> To breed these guys is very difficult. First off you need a large salt water source to simulate the sea, and a wave simulator. Second you would have to create a lunar cycle to induce breeding, maybe even a hibernation cycle.
> Third the young hatch from the eggs and spend quit a bit of time as plankton and only emerge out of the water after several molts as crabs.
> 
> It's pretty dificulte to breed these guys. No one has in capitivty as of yet at least. Thats why they show up as imports.
> ...


Do the young stay low in the water column near the bottom or high?  Do the young "plamkton" stage eat plant or animal plankton...or both?

If so, you can possible set up a small maturation tank.  The tank could be a 20 gallon with a false bottom.  Put 1 inch pvc pipes laid on their sides, then on top, place plastic "egg crate"...the checker board shaped plastic cover for flourescent fixtures.  Layer all this stuff about 6-12inches deep...the more the better.  Use a tall tank to maintain enough water column if necessary.

Then vinyl/fiberglass window screening, then coarse sand/coral gravel, more screening, then fine sand.  

Over a couple of months this set up will seed beneficial bacteria that will convert all nitrogen based waste(protien, ammonia, etc) into nitrites, then nitrates and eventually nitrogen gas...which means the waste will eventually bubble out of the tank.  Just buffer the water, add supplemental nutrients and fresh water to maintain salinity levels...the water will never go bad if done and maintained properly......yes, I mean no water changes.

A very good addition is a protien skimmer.  Dont run it during feedings, it'll snatch all the microscopic food particles out of the water before it can go bad...but also before the young can eat it. 

Hopefully the young will stay low in the column, so you can place a small power head at the water line, and the out flow to the water line also.

Now, the adult tank/habitat might not need any fancy moon-light simulations...being near a north facing window may provide enough ambient nigh cycles to stimulate them...Ive had coral and other marine animals do it without any moon exposure what so ever...some how they now.

If you can place a pool of salt water in the tank and leave them alone, they ma very well mate.  But I suspect you need to have minimal exposure to the habitat to allow them to be comfortable and secure enough to mate(benefits of my no water change set up for my reef tank).

If they mate, you can tray and collect the young and tranplant them to the maturation tank that needs to be up and running for a couple to few months before they hatch/are released.

If they stay low in the water column, they might not get sucked up into the protien skimmer(deadly).  If your not certain of their travel patterns(some plankton rise to the top of the column at night), I'd go without the skimmer, but it significantly impacts the ability to keep the water clean and not require water changes.  Any water changes are sure to stir them up and likly cause you to toss a lot of them out with the water change...becareful.

There are liquid feed for microscopic fry/young...Ive also learned how to culture algae(phyto-plankton I believe it is) too.  Its much cleaner, alive and less likly to cause nasty die offs since they can actually live awhile and not all die at once.

Be light with the feedings, keeping in mind that the bacterial colony seeded/seeding in the pleneum(under the false bottom) and in the sand can only handle so much.  The colony will grow to accomodate increases in waste, but its a slow process.

To speed the process up, buy whats called live rock and live sand.  Put some smaller pieces of live rock buried in the sand and in at the bottom of the false bottom with the PVC pipes...put the rest of the live rock on top of the sand.

This will seed the rank with both oxygen strains of bacteria above and non-oxygen using bacteria in the bottom where the water "stagnates"...well, actually it just doesnt move much.  The false bottom water will eventually be a low oxygen area and those specialized bacteria will consume the nitrate waste the oxygen bacteria above cant consume and it will bubble out of the tank.

whew! that was long.


----------

