Vampire crab care sheet!
Alright fellas, I’ve researched these crabs SO MUCH, and have been keeping them successfully for a while now, so I feel confident in writing a care sheet for you all. But before we begin, there’s the usual disclaimer to do your own research before purchasing any crabs, and that I in particular only have experience with Geosesarma hagen (also known as the Red Devil crab), so care may be different for other species. NOW LET’S GO!
Latin name: Geosesarma sp. (this care sheet is focused on hagen, but care is pretty much the same for all species)
Size: 2.5 cm in shell width is maximum for the commonly kept species. My male is only about 1.5 cm in shell width. So very smol.
Indigenous region: Geosesarma hagen lives wild on Java in Indonesia. Vampire crabs in general are found throughout most of the tropical regions in Asia, and Hawaii.
Indigenous environment: Vampire crabs spend their days hiding in the mud and various foliage you find besides creeks in the tropical regions of Asia. Here they hunt and eat tiny bugs, insects, and whatever else they can get their tiny claws on.
Set up: The best vampire crab set up is one that as close as possible resemble their natural environment, while also checking of the various boxes a vampire crab needs to be healthy. The most important aspects in having happy and healthy vampire crabs, are having a moist environment, a water source, and lots of hiding places. To keep their environment moist, an aquarium or glass (non wire-top) terrarium is the best. They do fine when kept at room temperature, but you may need a heating source, like a small UTH, if you’re planning on keeping the crabs in a cool area of your home. They can survive relatively low temperatures, but become less active and their metabolism slows the lower the temperature, which can be fatal over a longer period of time.
Enclosure size: A good starting point for a vampire crab enclosure is at least 5 gallons worth of floor space per 2 crabs in the enclosure, but more space is always better. That means that you can have at most, 2 crabs in a 5 gallon, 4 in a 10 gallon, 8 in a 20 gallon, and so on. If your tank is a long model, you can add one or two extra crabs per 5 gallons over 20 gallons. So a 20 gallon long tank can hold 9-10 crabs. But remember to design your tank, so that there is a place for each crab to hide, without having to share with the others.
Substrate: I recommend coco mulch as a substrate, as it’s great at holding in moisture (like sphagnum moss/peat) but is a realistically renewable ressource (unlike sphagnum moss/peat). 80-90% of your enclosure should be substrate, and your substrate should be pretty wet.
Water source: 10-20% of your enclosure should consist of at least one water source. Several smaller water sources are fine, the water just has to be deep enough for the crabs to completely submerge themselves. The easiest way to do this is to add a bowl or box into your substrate and fill it with water. I’ve used a Tupperware box. Make sure that the crabs can get in and out of your water source, I’ve done this by adding branches that connect my substrate and the bottom of the pool. You don’t generally need a filter, as crabs in a moist enough enclosure only really use the water source when they are stressed or before/after moulting. I just change out the water once a week. Be careful when you change it though, as both grown up and potential baby crabs like to hide in the water! Besides the water source, regular manual misting (about once a day) is recommended. Either that, or an automatic mister. Probably not needed if you keep the enclosure somewhere really moist.
Hiding places: As vampire crabs are very smol, you can imagine that many animals prey on them, they therefore need lots of hiding spots to feel secure from predators, and from other crabs when they are moulting. The best and easiest way to create hiding spots for your crabs is by copying from their natural environment. What do you usually find besides creeks? Leaf litter, various moisture loving plants, old branches and bark pieces, rocks and moss all help in creating lovely little nooks and crannies that the crabs can hide in. And a lot of the stuff can be bought cheaply at a plant nursery (miniature peace lilies, orchids, ferns and bromeliads are examples of plants you can find most places. Beware that some of these will outgrow your tank), and the rest of the stuff can be harvested from pieces of nature that you trust to be pesticide free. I’ve collected moss from my backyard lawn, and went to a nearby forest to collect small pieces of bark and branches for my crabs. You don’t need to disinfect the stuff you collect, just make sure there aren’t any venomous or poisonous creatures that might hurt your crabs. Small creatures like wood lice and ants are fine - the crabs will probably just eat them. Besides the natural elements, you can use whatever hides you would use in other aquariums or terrariums. For example, I have a mini dragon skull, and a coconut hide, found in the aquarium part of a pet store.
Gender ratio: Male vampire crabs are territorial, and can fight. They very rarely fight to the death, but they can be so stressed from fighting that they die. I therefore recommend more females than males, if you have the maximum amount of crabs for your tank size, so that males can get breaks from territory fights. If you’re keeping two crabs in a 5 gallon, they should either be two females, or one male and one female.
Sexual dimorphism: Male vampire crabs are more colourful than the females, and have bigger claws. They also tend to be slightly bigger when fully grown. It can be really difficult to tell if the crabs aren’t fully grown, as young crabs all look like females.
(Not G. hagen, but you get the idea)
Diet: Vampire crabs are opportunistic carnivores, and a big part of their diet in the wild consist of small bugs and insects that they catch. When live prey is unavailable, they scavenge and eat whatever they can find, including dead animals and algae. In captivity they can therefore be fed what you would feed a fish with the same eating habits. I feed my crabs with a varied diet of crushed high quality Betta pellets, frozen and thawed food like blood worms and cyclops, and flightless fruit flies once I get a colony going. I’ve tried with a small plate for their food, but they didn’t use it, so I just spread their food nearby them, and they find it. If you are keeping a bio active enclosure, you can take a bit of your CUC (like springtails or small isopods) and feed your crabs with them once in a while. They will love it. I also have a little lump of Java moss in their pool, so they can eat the algae from that if they want. They do once in a while!
Behaviour: Vampire crabs are more active at dawn and dusk, so a regular light cycle is needed, with either a timed light or natural light is needed. They are little fxckers that can stay out of view for so long (I’m talking weeks) that you are sure that they are dead, but then suddenly there they are! So don’t panic if you haven’t seen them for a while. One way they like to hide is to dig little caves into the substrate, which is why it’s important to have some open substrate for them to dig through.
(I’ll edit this later so it’s better, but for now I just want it out of my drafts lol)
