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crabmediumFreshwater

Pom Pom Crab

Ptychognathus barbatus

📍 Southeast Asia (Thailand, Malaysia)

Ask Finn

The Pom Pom Crab is a small, peaceful freshwater crab native to Southeast Asia, named for its distinctive feathery antennae that resemble pom poms. These crabs are filter feeders that spend much of their time sifting through substrate and water column for biofilm and detritus. They make excellent additions to planted tanks and are generally safe with peaceful fish and invertebrates.

Size0.75"
Min Tank10g
peaceful
Zonebottom

Care Guide

Diet

Pom Pom Crabs are filter feeders that primarily consume biofilm, algae, and organic detritus from the water column and substrate. Supplement with high-quality sinking pellets, blanched vegetables (zucchini, spinach), and occasional protein sources like bloodworms. A mature, established tank with abundant biofilm is essential for their long-term health.

Behavior

These crabs are nocturnal and spend most of their time on the substrate or plants, using their feathery antennae to filter-feed from the water. They are generally sedentary and peaceful, rarely interacting aggressively with tank mates. They may occasionally molt, during which they are vulnerable and should be left undisturbed.

Breeding

Breeding Pom Pom Crabs in freshwater aquariums is extremely difficult and rarely successful in captivity. Females may produce eggs, but larvae typically require brackish water to develop properly. Most specimens in the hobby are wild-caught, making captive breeding impractical for hobbyists.

Common Diseases

Molting Complications

Symptoms

Crab stuck in old exoskeleton, inability to fully shed, lethargy after molting

Treatment

Ensure stable water parameters and adequate calcium (via cuttlebone or mineral supplements); provide hiding places; avoid disturbance during molt; maintain pristine water quality

Shell Erosion / Calcium Deficiency

Symptoms

Soft or pitted exoskeleton, difficulty molting, visible shell degradation

Treatment

Add calcium supplements or cuttlebone to tank; increase water hardness (4-8 dGH); ensure varied diet with protein; perform regular water changes

Bacterial Infection

Symptoms

Discoloration, lesions on body or legs, lethargy, loss of appetite

Treatment

Perform 25-30% water changes; maintain pristine water quality with zero ammonia/nitrite; isolate if severely affected; consider antibacterial medication if condition worsens

Copper Toxicity

Symptoms

Lethargy, loss of appetite, erratic behavior, death

Treatment

Never use copper-based medications in tanks with crabs; avoid fertilizers and treatments containing copper; perform large water changes if copper exposure occurs; use activated carbon in filter

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Quick Facts

diet
Omnivore / detritivore / filter feeder
lifespan
2-3 years
max size
2 cm (0.75 in)
tank size
10 gallons minimum
temperament
peaceful

Water it likes

ph
6.5-7.5
ammonia
0 ppm
nitrate
<20 ppm
hardness
4-8 dGH
temperature
72–79°F (22–26°C)

Stats

Community tips0
Kept by0 hobbyists