Emerald Crab (Mithraculus sculptus)

The Emerald Crab (Mithraculus sculptus) is a freshwater invertebrate for planted and community aquariums. This profile covers habitat, diet, tank needs, and emerald crab care.

For related reading, see Nerite snail, Trochus Snail, Java Moss for shrimp cover and Turbo Snail.

Native Habitat and Size

Associated with Caribbean reefs. Adults reach 1.5–2 inches (4–5 cm).

Tank Requirements

Minimum: 20 gallon+ reef. Mature biofilm, hiding places, and copper-free water are essential.

Diet

Feeding mode: herbivore / omnivore. Supplement scavenging with species-appropriate wafers, vegetables, or powdered foods in current for filter feeders.

Water Conditions

  • Temperature: 74–80°F (23–27°C)
  • pH: 8.1–8.4
  • Ammonia / nitrite: 0 ppm

Compatibility and Breeding

Keep with peaceful fish. Breeding difficulty: beginner. Provide cover for berried females or egg clutches.

Conclusion

Emerald Crab adds cleanup behavior and interest when water quality stays stable and tank mates remain gentle.