It has been noted to consume filamentous cyanobacteria, diatoms, brown and red algaes such as seaweeds, seagrass, forams, hydrozoans, bryozoans, nematodes, bivalves, gastropods, crustaceans, and tunicates.

Unlike hemoglobin, the hemocyanin is not bound to cells but is simply dissolved in the hemolymph, the fluid part of the blood.

Keyhole limpet hemocyanin (KLH) is a copper containing respiratory protein, similar to hemoglobin in humans.

KLH is a large protein that acts as the hapten carrier part of the vaccine component, and is so far thought to be non-toxic.

The major potential use of KLH is for bladder carcinoma by stimulating a specific immune response, but there are many other medical uses such as stress assessment, understanding inflammatory conditions, and treating drug addiction.