Breeding the Pom-Pom Crab (Lybia tessellata)
Lybia tessellata is a tiny Indo-Pacific crab that carries living sea anemones in its claws for defense. Females brood eggs under the abdomen and release planktonic larvae, so home breeding is not achievable.
Overview
Lybia tessellata is a small crab of the family Xanthidae, reaching only 1–2 cm, found across the Indo-Pacific in warm shallow waters near rocks and coral. It is famous for carrying sea anemones in specialized hooked claws for defense and, in some cases, feeding. This anemone-carrying behavior in the genus Lybia is nearly obligate and is thought to have evolved during the Eocene.
Sexing
Sexes are distinguished by abdominal shape, with the female's broader apron accommodating the egg mass. A gravid female carries eggs within the abdominal apron, which makes brooding females identifiable on close inspection.
Conditioning
Maintaining a pair of healthy anemones per crab and offering fine particulate and meaty foods keeps the animal in condition. No documented protocol reliably triggers or completes reproduction in a home reef, because the larvae are planktonic and cannot be reared in a display.
Breeding Setup
No practical home breeding setup exists. Research suggests xanthid crabs are gravid during the summer months, with this group releasing eggs around September, though specific Lybia reproduction mechanisms remain poorly understood. The released larvae are planktonic and require open-water rearing.
Spawning & Larvae
The female broods fertilized eggs under the abdominal apron until they hatch into planktonic larvae that develop in open water before settling. Because juveniles also need to acquire their defensive anemones at settlement, by inducing splitting of an existing anemone or stealing one from a rival, captive rearing is impractical.
Common Challenges
- Planktonic larvae are removed by filtration and skimming.
- Larvae require continuous planktonic food.
- Settling juveniles must acquire defensive anemones.
- Active fish such as wrasses and hawkfish stress or prey on the small crab.