JOHNGARTHIA WEILERI CARE GUIDE – ROYAL NEBULA CRAB CARE
The Royal Nebula Crab, Johngarthia weileri
Author: Albos Invert’s
The Royal Nebula Crab, Johngarthia weileri, is a large terrestrial crab native to São Tomé. While not commonly available in the pet trade, it is highly sought after due to its super unusual colouration and durability. These crabs are often considered a dream replacement for Gecarcinus ruricola, offering similar behaviour and care requirements with a unique appearance. Their overall care is straightforward, so they are quite suitable for beginners but only if you know how to keep the correctly!
Common Names:
Royal Nebula Crab
São Tomé Land Crab
Members of the Species:
Johngarthia weileri (primary focus)
Conservation Level:
There is currently insufficient data available regarding wild population numbers or conservation status.
Care Level:
Dark Method: Beginner
Love Method: Beginner
Enclosure and Environment
These crabs are highly terrestrial and require a secure enclosure with ample land space. Enclosures should be escape-proof, as this species is strong and capable of climbing. Environmental conditions are very similar to Hartnollius species, though Johngarthia weileri grows larger and benefits from extra space.
Minimum Tank Size:
20 gallons (single crab only)
Temperature:
24–27 °C (73–80 °F)
Humidity:
~80%
Water Type:
Brackish water dish only
Salinity:
1.010
Substrate:
This species shows high tolerance for a wide range of substrates. Acceptable options include:
Gravel
Crushed coral
Bare bottom
Topsoil/sand mixes
At present, any commonly used substrate appears suitable, provided humidity is maintained and the enclosure remains clean.
Cohabitation:
❌ Not recommended
Highly territorial
Fighting and injury are very likely if housed together
Limb loss and fatalities may occur
This species should be housed singly.
Diet:
Omnivorous
Feed a balanced and varied diet including:
Vegetables
Fish pellets
Shrimp (fresh, frozen, or dried)
A consistent diet with both plant matter and protein is essential for long-term health and successful molts.
Feeding Frequency:
Every other day to daily, depending on portion size
Remove uneaten food to prevent mold and pest issues
The Royal Nebula Crab, Johngarthia weileri feeding
Breeding:
Not documented in captivity
Likely requires specific environmental triggers
No confirmed captive breeding reports at this time
Important:
Always house singly
Maintain stable humidity to prevent failed molts
Secure lids are essential: This species is an excellent climber
Data Source:
This guide is based on captive care observations and keeper reports from Albo’s Inverts and the team at Crustacean Council.