Petrolisthes eriomerusis commonly referred to as Flattop Crab, Porcelain Crab. Difficulty in the aquarium: There are no reports available yet that this animal has already been kept in captivity successfully. Toxicity: Toxic hazard unknown.
Petrolisthes eriomerus is a porcelain crab found in the eastern Pacific Ocean. It is commonly known as the flattop crab. It is a flattened, rounded animal, with a carapace up to 20 mm across. It is a filter feeder, and also sweeps on diatoms from rocks.
The color varies from dark brown or brownish-red to blue.. Blue mouthparts and blue spots at the joints of the pincers distinguish this species from the flat porcelain crab (Petrolisthes cinctipes). However, mouth and claws must be open to show colouration.