Halloween Moon Crab

[LOUofSPARTA]

Hi all, I've been getting prepared to get my first invertebrate, a Halloween Moon Crab (Gecarcinus quadratus). As I've been researching I've been trying to piece together a suitable environment.

So far I have purchased a 58l (12.5 gallon) aquarium. I understand this is around the minimum size to keep a single crab in. This crab is a land crab and cannot swim, it needs freshwater so it can keep its gills wet to breathe, usually given in a dish. It also needs special salt water for drinking as it will not be getting enough salt in captivity. I have also purchased a 30 litre (6.5 gallon) pump and accompanying equipment. I intend to make 1/4 of the tank water and the remaining area land. The crabs like to burrow and I don't want the water turning the substrate into a bog and suffocating them so I will be using a foam filter block and some hydro balls with a mesh filter on top to keep the water away from it. The setup will be very similar to this video (for vampire crabs) except the water area will be much smaller. A salt water dish will also be supplied. For substrate, I intend to use a mixture of coconut husk fibres with some organic black soil and ReptiSoil, this should be good enough to ensure their burrows do not collapse. I live in a cold and dry climate so I hope the dedicated water area help to keep the moisture. To combat the cold I will be looking into a heating pad to go on the side of the tank.

I would greatly appreciate any advice in setting this tank up.
Thanks.

 

[Liquifin]

12.5 gallon or 58L tank is way too small for a Gecarcinus quadratus. A lot of people are misinformed about these tank sizes, but for starters, the minimum of the enclosure size is a 20 gallon tank in terms of barely making it work. A lot of people should know that these species can grow anywhere from 4''-6'' inches or 10cm-15cm. I'm sorry to inform you, but the video of that enclosure will not work for the Gecarcinus quadratus as they will actually burrow to the very bottom and dig around and out the clay balls. Also avoid using any plants at all whether fake or real as Gecarcinus quadratus are notorious for eating any plants whether live or fake as they are primarily scavengers.

 

[LOUofSPARTA]

12.5 gallon or 58L tank is way too small for a Gecarcinus quadratus. A lot of people are misinformed about these tank sizes, but for starters, the minimum of the enclosure size is a 20 gallon tank in terms of barely making it work. A lot of people should know that these species can grow anywhere from 4''-6'' inches or 10cm-15cm. I'm sorry to inform you, but the video of that enclosure will not work for the Gecarcinus quadratus as they will actually burrow to the very bottom and dig around and out the clay balls. Also avoid using any plants at all whether fake or real as Gecarcinus quadratus are notorious for eating any plants whether live or fake as they are primarily scavengers.

Thank you for the information! You seem to know quite a bit about these. Given the tank size, I believe I can deal with that over time by eventually getting a larger tank. As for the burrowing, if the crab getting to the clay balls would be an issue, surely wire mesh would be enough to keep them out. If not, what would you recommend? Understood about the plants being an issue, things likes rocks would suffice. Do you think these changes would be suitable?

Thanks.

 

[Liquifin]

Thank you for the information! You seem to know quite a bit about these. Given the tank size, I believe I can deal with that over time by eventually getting a larger tank. As for the burrowing, if the crab getting to the clay balls would be an issue, surely wire mesh would be enough to keep them out. If not, what would you recommend? Understood about the plants being an issue, things likes rocks would suffice. Do you think these changes would be suitable?

Thanks.

One huge problem is that Gecarcinus quadratus are crabs, and crabs will move and destroy things regularly. From what I can say, they will destroy or move the mesh if they have too. Not to mention how strong they are at times as they literally will move decorations and they will bury them at times. I suggest that if anything gets buried or moved, I suggest just leaving it alone. Because they will constantly move anything on the surface and dig to the bottom of the enclosure. You're basically aren't going to have a beautiful looking display enclosure as they are construction and destruction artists. They will excavate the surface and dig to their maximum depth no matter what. You can provide them with as much depth as you like, but they won't stop until they hit the very bottom in most cases.

If you cannot find a way to divide the enclosure between water and land completely, then a water bowl is going to have to do. The only problem with them is that they can bury them often or move them like a work out. You're going to have to work with them in terms of providing water to their gills. It gets annoying at times, but you'll get use to it over time.

Every time I try to fix or dig out decorations (excluding buried water dishes) that were buried, it tends to stress them out a lot. So I've come to terms to leave it alone unless I have to dig it out for substrate changes or maintenance. Rocks and cork/drift wood would do fine as decorations and hides. Make sure the rocks are not heavy so it doesn't crush them if you're using them. Note that they will retreat every time when exposed to light, when seen, or startled. They're very shy and will only come out at night for food and for exploration. Make sure your enclosure is escape proof because they can climb very well to anything with a rigid enough surface. This including wood, decor, etc. not to mention how good their grips are with the pincers.

Feeding schedules is highly and still strongly debatable, so I can't tell you what is an ideal feeding schedule. But diet wise, they will eat just about anything they can scavenge. Some people say they will take meat and insects frequently, but I suggest keeping that to a minimum as I find them to be more vegetarian. In terms of protein for their diet there is a lot of mixed opinions on the subject. Many suggest using bone marrow as a source of protein, but I find that some small cut pieces of meat work just fine. Now I'm not saying cut meat is ideal for protein, but it works for me. Some people use hermit crab pellets as some say it has protein? In terms of fruits and vegetables, they favor dark greens such as lettuce, kale, etc. and some fruit mixed in. Whatever they don't eat within 2-4 days, I would take it out. They will sometimes take food into their burrows and save it or eat it later in some cases. It's good to vary their options as I find that only providing one kind of food will actually turn them off to eating. So try to vary their diet in terms of veggies and fruits to get them to eat. That's about all I can think of at the moment.

 

[goliathusdavid]

@LOUofSPARTA I just want to say that I am glad that you came here and are trying to provide the best care. In my experience 9 times out of 10 people keeping crabs are not providing proper husbandry because they don't do their research, something which can occasionally prove lethal particularly in the cases of species such as Birgus latro (something which has recently started being offered in the US). Completely agree with all the advice of @Liquifin, these need lots of space and are far more difficult to keep than you might think.

 

[LOUofSPARTA]

@LOUofSPARTA I just want to say that I am glad that you came here and are trying to provide the best care. In my experience 9 times out of 10 people keeping crabs are not providing proper husbandry because they don't do their research, something which can occasionally prove lethal particularly in the cases of species such as Birgus latro (something which has recently started being offered in the US). Completely agree with all the advice of @Liquifin, these need lots of space and are far more difficult to keep than you might think.

After reading the most recent reply from @Liquifin, I don't think that in my current setup I will be able to care for the Gecarcinus quadratus properly, particularly due to their size, demands and my general inexperience. I don't believe a 58 litre tank will be sufficient for them to live happily and in isolation (I could make the tank bigger eventually but even now I only have room for one) and I don't have enough experience/knowledge to meet all their needs. The misinformation around online has certainly given me a warped perception of the level of care for the Gecarcinus quadratus.

From the beginning I had been looking at multiple crabs and so far I have found a lot more information regarding Vampire Crabs (Geosearma). There are a lot more guides, videos and general care regarding them. There is even someone in these forums I have seen who has bred them in captivity! Due to their smaller size they seem to be a lot less destructive and more suitable for my situation, but again I will have to research more into them until I have a concrete plan of action.

Thanks.

 

[Erinlisahall]

Can someone show me their moon crabs set up? I instantly adored these guys at an expo and brought 2 home. I bought the tub they were in from the seller and the have 6" substrate and 2 bowls right now, but they aren't burrowing or hiding and I know I need to get a good setup going soon before they get dangerously stressed. They are eating well and are so great! Care info is all over the place on enclosure size.... I was looking at a 29 gallon aquarium but I can go bigger with a tub if that's better for them.... what water bowls do u use? Ceramic seems to work. I've got 2 of each salt and fresh cuz they tip em lol. I work from home so I can keep fillin.