Sally Lightfoot Crab care guide
Sally Lightfoot Crab (Percnon gibbesi) — minimum tank 100 L, temperature 24-26 °C, pH 8.1-8.4.
Compiled by Aquairi from published sources · Published · Updated
Overview
Sally Lightfoot Crab (Percnon gibbesi) is a marine spray crab of the family Percnidae, listed in the Aquairi knowledge base as an intermediate-level species. Fast flat-bodied crab with red, yellow and blue colors. Excellent algae grazer when small but eats fish, shrimp, and invertebrates as it grows. Switch out at adult size.
Taxonomy
- Family: Percnidae
- Genus: Percnon
- Scientific name: Percnon gibbesi
- Common synonyms: Nimble Spray Crab, Urchin Crab
Habitat
Percnon nimble spray crabs (family Percnidae) are flat, fast-moving reef crabs of tropical seas that dart across rock and live among the spines of sea urchins for shelter. They graze algae and scavenge on the reef. In the Aquairi knowledge base this species is recorded from Caribbean, Eastern Pacific, Mediterranean (invasive).
Tank requirements
- Minimum tank volume: 100 L (26.4 US gal)
- Adult size: 5-8 cm
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- GH: 8-12 °dGH
- KH: 8-12 °dKH
- Salinity (specific gravity): 1.024-1.026
- Lifespan: 2-5 years
Diet
The species is an omnivore, grazing algae, biofilm and detritus across the rockwork and substrate; in aquaria its diet is supplemented with dried algae and sinking foods when natural growth is scarce.
Compatibility
The Aquairi knowledge base lists this species as semi-aggressive. Suitable tank mates include Large fish (juvenile only). It should be kept away from Small inverts, Slow fish, Coralline-rich SPS reef. This species is not fully reef-safe and may pick at corals, sessile invertebrates or small tank mates.
Breeding
Breeding requires an extended planktonic larval stage in open water before the young settle, which makes captive reproduction very difficult and rarely accomplished in home aquaria. Most specimens in the hobby are wild-collected.
Breeding the Sally Lightfoot Crab (Percnon gibbesi)
Overview
Percnon gibbesi is a flat, fast-moving crab of the family Percnidae with a carapace about 30 mm wide and spined walking legs. It is native from California to Chile in the Pacific and Florida to Brazil in the Atlantic, and is strictly herbivorous; in the Caribbean it associates with the sea urchin Diadema antillarum. It is described as the most invasive decapod to enter the Mediterranean, first recorded at Linosa, Sicily in 1999.
Sexing
Sexes are distinguished by abdominal shape, and a gravid female is recognized by the egg mass carried beneath the abdomen on the pleopods. Egg-carrying females have been recorded off West Africa between February and April and in August.
Conditioning
An algae-rich environment supports this herbivore, but adults become predatory as they grow and are best kept singly with robust tankmates. No documented protocol reliably induces 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. The female broods fertilized eggs until hatching, then releases larvae into the water column. These larvae are planktonic and long-lived, a trait that contributes to the species' invasiveness, and they require open-water rearing conditions.
Spawning & Larvae
Hatched larvae enter the plankton and remain there for an extended period, developing through molts before settling. This long-lived planktonic phase is exactly what makes the species so good at colonizing new regions and what makes captive rearing impractical.
Common Challenges
- Long-lived planktonic larvae are removed by filtration and skimming.
- Larvae require continuous planktonic food over a prolonged period.
- Adults turn predatory and may eat tankmates and invertebrates.
- Never release this invasive species into the wild.