The Red Devil Crab (Geosesarma hagen) is a stunning semi-terrestrial species native to the lush tropical forests of Southeast Asia, particularly Indonesia and Java. This crab species is widely admired for its bright red carapace, purple-tinted claws, and vivid eyes, which make it a centerpiece in any paludarium or semi-aquatic setup.

🌿 Habitat and Setup

Red Devil Crabs thrive in paludarium-style environments, which combine both land and water. A ratio of 70% land and 30% shallow water works best. Provide multiple hiding spots using driftwood, stones, and live plants such as Java moss or Anubias. The water should be lightly brackish (optional but beneficial) with excellent filtration and gentle flow.

Substrate Recommendation: Use moist coco fiber or sand on the land area to retain humidity. Mist the enclosure daily to maintain 80–90% humidity.

🌡️ Water and Temperature Parameters

Maintain the water temperature between 24–28°C (75–82°F) and a pH range of 7.0–8.0. Regular partial water changes and dechlorinated water are crucial to prevent stress and ensure longevity.

🍽️ Diet and Feeding

The Red Devil Crab is omnivorous and enjoys a variety of foods such as:

• Frozen or dried bloodworms

• Shrimp pellets

• Blanched vegetables (zucchini, spinach)

• Occasional insect treats (e.g., crickets or fruit flies)

Feed small portions 3–4 times a week, ensuring food is accessible on land areas.

🧠 Behavior and Compatibility

These crabs are territorial and mildly aggressive, especially males. It’s best to keep one male with multiple females or maintain a single pair in smaller setups. Avoid mixing with fish or other crab species.

❤️ Why Choose the Red Devil Crab?

• 🌈 Brilliant red coloration

• 🪸 Perfect for small terrariums and paludariums

• 🧩 Easy care for beginners

• 🦀 Fascinating semi-terrestrial behavior

• 💧 Helps maintain natural ecosystem balance