Anemone Crab

Anemone Crab: The Filter-Feeding Host-Dweller

The Anemone Crab (Neopetrolisthes ohshimai), also widely known as the Spotted Porcelain Crab or Porcelain Anemone Crab, is a fascinating and peaceful addition to the reef aquarium. Despite its common name, it is not a true crab but a member of the family Porcellanidae, making it more closely related to squat lobsters.

Native to the Indo-Pacific, this crab is known for its beautiful, relatively flat body, often white or cream-colored with light purple to brown spots. Its large front claws are for defense, but its distinguishing feature is a pair of modified, fan-like mouthparts (maxillipeds) it uses for filter feeding in the water column.

In the wild, this species forms a commensal relationship with large host anemones (such as Bubble Tip, Carpet, or Sebae anemones), which provide protection from predators. In the home aquarium, while it is happier with a host, it can thrive among live rock, provided it receives sufficient planktonic food.

Diet & Compatibility:

• Diet: The Anemone Crab is a Carnivore / Filter Feeder. Its natural diet consists of suspended micro-particles, phytoplankton, zooplankton, and detritus it filters from the water. In the presence of an anemone, it also consumes mucus and food particles dropped by the host.
• Feeding: Unlike general scavengers, these crabs rely heavily on particles in the water column. They require regular broadcast feeding of live phytoplankton, rotifers, copepods, or high-quality powdered coral foods to supplement their diet, especially in very clean tanks. Target feeding small, meaty foods near their resting spot can also be successful.
• Reef Compatibility: It is Reef Safe With Caution. It will not harm corals, but caution is necessary when kept with a host anemone and aggressive fish. It is highly sensitive to copper-based medications.
• Temperament: It is Peaceful. It is generally docile but can be territorial toward its own species (conspecifics), making it best kept singly or in a proven male-female pair. Avoid housing it with predatory fish (Triggers, Puffers, large Wrasses, or Dottybacks) or large, aggressive shrimp/crabs that may attack it, especially during molting.
• Clownfish Competition: If housed with an anemone and a mated pair of clownfish, the clownfish will generally prevail and may aggressively exclude the crab from the anemone.

Quick Facts

• Scientific Name: Neopetrolisthes ohshimai
• Primary Common Name: Anemone Crab
• Other Common Names: Spotted Porcelain Crab, Porcelain Anemone Crab, Spotted Anemone Crab
• Origin: Indo-Pacific
• Max Size: 1-2 inches (2.5-5 cm) in carapace width/leg span
• Temperament: Peaceful (Territorial with same species)
• Diet: Carnivore / Filter Feeder (Requires regular planktonic feeding)
• Minimum Tank Size: 10 Gallons (Smallest nano-tanks)
• Reef Compatibility: Yes (Caution with anemone hosts/predators)