The freshwater Pom Pom crab (Ptychognathus Barbatus) is a fully aquatic species and a fairly new entrant to the aquarium hobby. They’re loved for their gentle nature but it’s their appearance that makes them stand out. These little crabs have Pom Pom-like tufts growing from each claw joint.
Pom Pom crabs are incredibly small, topping out around 1 inch at their full size. Though they’re one of the smallest freshwater crab species in the aquarium hobby, their carapace is unusually broad and their legs are very long and slender. These crabs are typically pale yellow or brown in color, though their color can change to match their environment.
Differentiating between male and female Pom Pom crabs is fairly straightforward. In males, the plate on the underside of the body known as the apron is thin and narrow. Females have a wide, curved apron. Males of the species also tend to have larger claws and “pom poms” as well.
Like many crustaceans, the Pom Pom crab is a scavenger. These little crabs are opportunistic omnivores, so they’ll eat just about anything they can get their claws on. Aquarium hobbyists sometimes make the mistake of thinking these crabs are filter feeders, but the food they catch in their hairs doesn’t account for the majority of their consumption.
Pom Pom crabs make wonderful additions to a freshwater cleanup crew because they will scour your tank for algae, plant detritus, and microorganisms to feed on. These crabs will eat most commercial foods and should be offered live or frozen foods like brine shrimp or bloodworms on occasion. Because these crabs scavenge for food, you may only need to supplement their feeding 2 to 3 times per week.