Pom Pom Crab Care Guide: Freshwater Ptychognathus in Nano Tanks
Freshwater pom pom crabs are among the most charming invertebrates available to nano tank enthusiasts. This pom pom crab care guide from Gensou Aquascaping Singapore, backed by over 20 years of hands-on aquascaping experience at 5 Everton Park, covers housing, feeding, and husbandry for Ptychognathus barbatus. A thorough pom pom crab care approach rewards keepers with fascinating behaviour rarely seen in other freshwater crustaceans.
Species Background
Ptychognathus barbatus earns its common name from the distinctive tufts of setae — hair-like filaments — on its chelipeds (claws). These tufts resemble tiny cheerleader pom poms, constantly waved through the water to filter-feed on microorganisms. Adults measure just 2–3 cm across the carapace, making them ideal for compact setups.
Native to freshwater streams in Southeast Asia, pom pom crabs are fully aquatic — an important distinction from many hobbyist crabs that need land access. They spend their lives submerged, which simplifies tank design considerably.
Tank Size and Setup
A 15–20 litre nano tank comfortably houses two or three pom pom crabs. Provide plenty of hiding spots using driftwood, coconut shells, and rock caves. Java moss and Bucephalandra attached to hardscape give the crabs surfaces to graze on while adding visual appeal.
Sand or fine gravel substrate works best. These crabs are skilled escape artists — even a small gap in the lid invites trouble. Use a tight-fitting cover, especially in Singapore where open-top rimless tanks are popular. A sponge filter keeps flow gentle and protects tiny limbs from impeller-driven filters.
Water Parameters
PUB tap water, once treated for chloramine, falls within acceptable range. Maintain pH 6.5–7.8, GH 4–15 dGH, and temperature 22–28 °C. Singapore’s ambient warmth of 28–30 °C means no heater is needed for most of the year. Stability matters — avoid drastic swings from large water changes.
Change 15–20 % of the water weekly. Copper-based medications are lethal to crustaceans, so keep this in mind when treating community tanks. Even trace copper in fertilisers should be monitored.
Diet and Feeding
Pom pom crabs are omnivorous filter feeders and scavengers. They wave their chelipeds through the water column, trapping suspended particles. Supplement this natural feeding with sinking pellets, blanched spinach, crushed algae wafers, and occasional frozen bloodworms.
Feeding every other day prevents waste buildup in small volumes. Scatter food near their hiding spots during evening hours when they are most active. A calcium-rich diet — cuttlebone fragments or mineral supplements — supports healthy moulting.
Behaviour and Social Dynamics
Primarily nocturnal, pom pom crabs spend daylight hours tucked inside crevices. After lights-out they emerge to forage, waving their pom poms methodically. Watching them under moonlight LEDs is genuinely entertaining.
Males may scuffle over territory, but injuries are rare when adequate hiding spots exist. Keeping a ratio of one crab per 8–10 litres minimises conflict. They coexist peacefully with small shrimp species like neocaridina, though very tiny shrimplets may occasionally be caught.
Compatible Tank Mates
Micro rasboras, pygmy corydoras, and otocinclus share similar water needs and pose no threat. Avoid large or aggressive fish — anything that can fit the crab in its mouth will likely try. Bettas are a gamble; some ignore the crabs, others attack.
Neocaridina cherry shrimp cohabit well and add colour to the nano setup. Both species appreciate biofilm-covered surfaces and planted tanks.
Moulting and Health
Crabs moult periodically as they grow, shedding their exoskeleton in one piece. The freshly moulted crab is soft and vulnerable for 24–48 hours — ample hiding spots are essential during this period. Leave the old exoskeleton in the tank; the crab often consumes it for mineral recovery.
Failed moults are the leading cause of death and usually stem from insufficient calcium or mineral content. Maintaining GH above 5 dGH and supplementing with calcium-rich foods greatly reduces this risk.
Sourcing and Pricing in Singapore
Pom pom crabs appear sporadically in local fish shops and more reliably through online hobbyist groups on Carousell. Expect to pay $5–$8 per crab. Inspect arrivals for all eight walking legs and intact pom pom tufts before purchase.
Following this pom pom crab care guide ensures these delightful crustaceans thrive in your nano aquarium. Gensou Aquascaping recommends them as a captivating alternative to shrimp-only setups — their constant waving motion adds a unique dynamic few other species can match.
Related Reading
emilynakatani
Still Have Questions About Your Tank?
Drop by Gensou Aquascaping — most walk-in questions get answered in under 10 minutes by someone who has set up hundreds of tanks.
5 Everton Park #01-34B, Singapore 080005 · Open daily 11am – 8pm
