Red Devil Moon Crab

Scientific Name: Cardisoma armatum (often sold as “Red Devil” or “Rainbow Moon Crab”)
Age: few months 
Current Size: 1-3”
Max/Adult Size: 4–6 inches (carapace)
Source: Wild
Exact Animal Pictured?: no 

Care

• Temperature: 78–85°F
• Humidity: 70–85% (high humidity required)
• Recommended Enclosure Size: Minimum 20‑gallon long for one; larger for groups
• Substrate: Deep, moist substrate for burrowing (eco‑earth/sand mix)
• Water: Brackish water dish required (1.005–1.010 SG); land area must dominate
• Lighting: Low–moderate UVB recommended

Facts

• Red Devil Moon Crabs are known for their electric coloration—deep purples, reds, oranges, and bright white claws.
• They are semi‑terrestrial, spending most of their time on land but needing access to brackish water for proper health.
• Highly territorial, especially adults; provide hides and visual barriers if housing multiples.
• Excellent diggers that will create complex burrows, so deep substrate is essential.
• Native to West African coastal regions, where they live in mangroves, beaches, and