Food and Feeding 

Avid generalists, wild Geosesarma are invariably found picking at decaying matter, grazing on algae, and stalking other invertebrates along their stream-side homes. Thankfully, this willingness to accept all manner of foodstuffs makes these crabs easily satiated in a captive setting. Sliced vegetables, fish flakes/pellets, and most especially, live arthropod prey are all consumed with gusto. It should also be noted that the ‘clean-up-crew’ (springtails, isopods, etc.) are also on the crab’s menu and should be restocked frequently if one wishes to maintain a steady population in a Geosesarma setup. 

The appetite of these high-metabolism organisms is not to be underestimated; Geosesarma are eager opportunists who rarely pass on a meal. One of the author’s vivariums went unstocked with crabs for 3 months and grew a flourishing Armadillidum population, only for it to be almost completely decimated within six weeks of adding five G. tiomanicum. While perhaps a bit frustrating for those who’d like both in their tanks, it should comfort the reader to know the isopods do serve as a fantastic food source. McMonigle (2018) reports juvenile Geosesarma fed on Porcellio experience a significant boost in growth rate, theoretically due to their soft, easily accessible calcium content. Needless to say, whether or not an active isopod population is desired within the setup, a separated external culture is invaluable to anyone looking to breed these crabs.

Yet these crabs can also be succesful when fed crickets, mealworms, and a variety of other feeders. They're not picky!!

References: 

1. McMonigle, O. (2018). Breeding the Vampire and Other Crabs (Brachyura and Anomura in Captivity) Husbandry, Reproduction, Biology and Diversity. Coachwhip Publications.