Limulus polyphemus | SHOW

Limulus polyphemus, commonly known as the horseshoe crab, is a remarkable marine invertebrate with a distinctive, prehistoric appearance. This species is not a true crab but belongs to the class Merostomata, making it a unique addition to specialised marine aquariums.

Care Level: Due to their specific environmental needs and diet, horseshoe crabs are recommended for experienced aquarists. They require stable water conditions and a large, well-maintained tank.

Tank Requirements: A minimum tank size of 180 litres (approximately 50 gallons) is advised to provide ample space for movement and to maintain water quality. A sandy substrate is essential to mimic their natural habitat and allow natural burrowing behaviour.

Water Parameters: Maintain stable marine conditions with temperature between 20-25°C, salinity at 1.023-1.025 specific gravity, and pH around 8.1-8.4. Moderate water flow is preferred to replicate coastal environments without stressing the animal.

Feeding: Limulus polyphemus is a scavenger and detritivore, feeding primarily on small molluscs, worms, and organic detritus. In captivity, provide a varied diet including chopped seafood such as mussels, shrimp, and specialised invertebrate pellets to ensure nutritional balance.

Compatibility and Reef Safety: This species is generally peaceful but may disturb small, slow-moving invertebrates due to its foraging behaviour. It is considered reef safe with caution, as it may inadvertently damage delicate corals or sessile invertebrates while searching for food.

Placement: Place Limulus polyphemus on a fine sandy substrate in a low to moderate flow area of the aquarium. Avoid sharp decorations or rough substrates that could injure its delicate underside.

Additional Notes: Horseshoe crabs are sensitive to poor water quality and sudden changes in parameters. Regular water changes and monitoring are essential. They are nocturnal and may be more active during the evening.