Freshwater Crab Darwin 8cm

Freshwater Darwin Crab

The Darwin freshwater crab has been a fairly recent but extremely popular species in the aquarium trade. This species is a true eye-catcher and is the perfect aquatic addition for experienced aquarists chasing an oddball species. Freshwater crabs are surprisingly easy to care for however they need a tailor-made environment for them to thrive which just makes them more fun, that added challenge and satisfaction received when they thrive is amazing to experience. 

One of the best things about the Darwin Freshwater crabs is that they are a true freshwater species meaning they live, breed, and complete their life cycle in full freshwater environments! This means that there isn’t the added hassle of creating brackish water to make them thrive and they make for a great interactive breeding project as well.

The Darwin Freshwater crabs are unique in their colours as well, the upper half of their shell has a chili red colour with a black nape right on top of their carapace (the shell of their body). The underside of their body gradients into a creamy yellow colour which makes these freshwater crabs a pretty and colourful species.

These freshwater crabs are incredibly hardy as well, they can be kept in a range of temperatures but because of their tropical origin, it is best to heat the aquatic portion of their environment to 24 degrees to maintain a warm and tropical setting. It is best to keep these crabs in a group of at least 3 or more individuals as this makes them feel more comfortable in their environment which also means they spend more time in the open. Plus, more crabs are just cooler! Because freshwater crabs are crustaceans, they go through a really interesting molting process. Crabs have an exoskeleton which is their hard protective shell however as the crab grows the shell does not. This means that the crabs break out of their shell once they get big enough and let the new shell they have been growing harden. It's a truly weird but mesmerizing experience to see them go through a molt and it often tricks a lot of freshwater crab keepers as they think their crab has died when it is actually an old shell that the crab has grown out of.

Breeding the Darwin freshwater crabs is possible in a captive environment however due to their fairly recent introduction into the aquarium trade there is not much information easily available on the process. In the wild, however, females develop a clutch of roughly 100- 350 eggs on the underside of the belly and release them in highly vegetated areas. The baby crabs then need to fend for themselves meaning that it might be best to have a dedicated breeding aquarium for captive success. Sexing the crabs however is an easy task, when having a look at their belly the males will have a V-shaped flap whereas females will have a more U-shaped flap. Males may also be more colourful as well. When handling the crab care should be taken because though they remain small and max out at around 6-7 cm they do have sharp pincers, when they grab hold it can cause immense pain and even draw blood. The crabs may also get stressed and drop a pincer as a defense mechanism which can lead to infection for the crabs. The wild origin of the Darwin Freshwater crab is surprisingly not just exclusive to Darwin, they are found all through the upper parts of Western Australia, Queensland, and the Northern Territory. 

Tank Recommendations for your Darwin Freshwater Crab
Darwin freshwater crabs have an amphibious lifestyle which is incredibly important to maintain. They spend equal amounts of time in the water as they do on land and they require atmospheric air for their gills to properly operate. As long as these crabs remain wet, they can remain on land for long periods. They only reach a maximum size of around 6 cm but are fairly round, the minimum aquarium for them would be 60 cm x 30cm x 30cm which allows a good footprint and adequate height for building a land area and having a good aquatic environment as well. Scape materials like driftwood and large stones allow for additional climbing areas for the crabs as well however a tight-fitting lid is a must as they can be excellent escape artists. The crabs may also eat plants due to their scavenging nature but fast-growing plants such as java moss and java ferns. 

Suitable Tank Buddies

Freshwater crabs are incredibly opportunistic meaning that no tank mate is safe aside from other crabs. Even then if there is not enough space in the aquarium the crabs can become territorial and end up fighting. If the choice of keeping them with fish is made it is best to keep them with fish that are fast and spend their time on the upper parts of the water column

Usually Compatible

Other freshwater crabs

Sometime Compatible

Giant danios, Murray River rainbow fish, and other fast-moving species however there is still always going to be a risk of being eaten. 

Rarely Compatible 

Neon tetras, angelfish, and predatory species such as turtles or large cichlids. 

Feeding your Darwin Freshwater Crabs

Feeding the Darwin freshwater crabs is a breeze as they take to a wide range of foods. It is best to give them quality high protein sinking pellets. They can also be supplemented with some frozen foods or live worms which will be a great, healthy food source. Freshwater crabs will also eat greens as well so giving them the occasional blanched veggies and nori sheet is good.  Feeding should occur once a day and it is best to do so when the lights are on.