Horseshoe Crab (Limulus Polyphemus)

Species Name : Limulus Polyphemus

Care Level : Easy

Temperament : Peaceful

Color : Tan

Diet : Carnivore

Reef Compatible : No

Water Conditions : 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.023-1.025

Max. Size : 12 inches

Origin : Atlantic Ocean

Family : Limulidae

Supplements : Calcium, Magnesium, Iodine, Trace Elements

Minimum Tank Size : 180 gallons

Horseshoe Crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are chelicerates, most closely related to arachnids, such as spiders and scorpions.

The Horseshoe Crab (Limulus Polyphemus) is greenish brown to light tan in color. They have a hard, rounded exoskeleton, a spike-like tail and five pairs of jointed legs. Their widely spaced eyes look like bumps on the top of their shell. Their gills have folds of membranes that look like the leaves of a book. A horseshoe crab picks up food with appendages located in front of its mouth. Because it has no mandible or teeth, the horseshoe crab crushes food between its legs before passing it to the mouth. Horseshoe Crabs can grow quite large. The female horseshoe crabs usually grow larger than the males, with their body reaching a maximum size of 12 inches  in diameter. 

The Horseshoe Crabs dig through sand and gravel in search of worms and any organic debris. It will move the substrate around almost nonstop in its search for food. They are reef safe, but when they attain a large size, can be harmful to fish and invertebrates, especially worms and clams.

Although it may find some food scavenging, its diet should be supplemented with meaty items such as pieces of squid and shrimp.

Size: Small: 1" to 2"; Medium: 2" to 3"; Large: 3" to 4"