Scientific name - Limulus polyphemus Family – Limulidae Common name – Horseshoe Crab Max Size – 12 in (30 cm) For the smaller species Min. Aquarium size – 180+ gal Range: Atlantic Ocean Care Level – Easy Temperament – Peaceful Foods and feeding – This crab will search through the sand bed looking for food, but its diet need to be supplemented with quality meaty foods. Most will starve in captivity. Supplements: Calcium, Magnesium, Iodine, Trace Elements Aquarium suitability - Please leave this creature in the ocean. Reef compatibility – With Caution Captive care – The horseshoe crab requires a large (10 sq ft), deep (6+ in) sand bed for them to dig in looking for food, but the do need a supplement diet. They can cause rock structures to fall over as they move the sand bed around. When they are larger they can harm other creatures in the tank, such as worms and clams as they root around. Crabs are extremely sensitive to nitrates and copper and small amounts will kill them.