Striped Shore Crab

Geographical Origin and Habitat: Native to the Northeastern Pacific coast (Oregon to Mexico) and introduced to the Northwestern Pacific (Japan, Korea). Inhabits rocky intertidal zones, tide pools, and harbor walls.

Taxonomy: Classified under the family Grapsidae. Features a squarish, slightly convex carapace with distinct transverse parallel stripes. Claws are large and robust. Reaches 4-5 cm.

Social Behavior: Highly active, territorial, and competitive. Frequently fights with conspecifics or other crab species over food, shelter, or dry basking areas.

Coloration and Sexual Dimorphism: Dark green, olive, or reddish-brown body with clear horizontal bands of red, purple, or lighter green. Claws are tinged with reddish-purple. Males grow larger and have heavier claws.

Tank Setup: Requires a cold-water marine or brackish setup. Best kept in a paludarium configuration with large flat rocks emerging from the water to allow basking. Tight lid is mandatory to prevent escapes.

Diet and Feeding: Opportunistic omnivore. Grazes on green algae and biofilm, but also preys on small snails, worms, and organic remains. Readily accepts fish food pellets and frozen meats.

Water Quality: Prefers cool temperate waters (12-22°C) and stable pH of 7.8-8.4. Sensitive to high nitrates and requires zero copper concentration.

Compatibility and Tankmates: Unsuitable for tropical reef tanks. Avoid keeping with slow bottom-dwelling fish or small snails as they will be eaten. Best housed in a dedicated shoreline biotope tank.

Aquarium Breeding: Females carry orange eggs under their abdomen. Larvae pass through five pelagic zoeal stages which do not survive standard aquarium filtration.

Risks and Diseases: Failed molts due to low iodine or calcium levels. High escape risk due to their agility and strength in climbing cables and corner joints.