Alex Mustard / Large whip goby (Bryaninops amplus) with a parasitic copepod (with two trailing egg ribbons) perched on Red whip coral. Whale Rock. Fiabacet Islands, Misool, Raja Ampat, West Papua, Indonesia. Ceram S...

Doug Perrine / Parasitic copepods {Copepoda sp.} on snout of Hammerhead shark {Sphyrnidae sp.} Bahamas

David Fleetham / Parasitic Copepod (Copepoda) on Whip coral goby (Bryaninops amplus), on whip coral, (Junceella fragilis), Indonesia.

Tony Wu / Parasitic copepod in the Caligidae family (possibly Caligus sp. or Lepeoptheirus sp.),that was associated with a Ocean sunfish (Mola mola) ocean sunfish. The long appendage visible at the rear end is...

Franco Banfi / Greenland shark (Somniosus microcephalus) with parasitic copepod (Ommatokoita elongata), under ice, Lancaster Sound, Nunavut, northern Baffin Island, Canada, Arctic.

Franco Banfi / Greenland shark (Somniosus microcephalus) with parasitic copepod (Ommatokoita elongata), under ice, Lancaster Sound, Nunavut, northern Baffin Island, Canada, Arctic.

Franco Banfi / Greenland shark (Somniosus microcephalus) with parasitic copepod (Ommatokoita elongata), under ice, Lancaster Sound, Nunavut, northern Baffin Island, Canada, Arctic.

Doug Perrine / Spotted eagle ray (Aetobatus narinari) with parasitic copepod attached to snout, Turneffe Atoll, Belize.

Franco Banfi / Greenland shark (Somniosus microcephalus) with parasitic copepod (Ommatokoita elongata), under ice, Lancaster Sound, Nunavut, northern Baffin Island, Canada, Arctic.

Georgette Douwma / Nudibranch {Risbecia tryoni} starting mating. The two purple sausage shaped structures by the gill are the eggs sacs of a parasitic copepod living inside the slug. Rinca, Indonesia

David Shale / Deep sea Parasitic copepod {Copepoda} from the mid-Atlantic ridge, depth 100-150m, at night

David Shale / Sand eel {Ammodytes tobianus} from Barents sea, Northern Europe, with parasitic copepods on tail

David Shale / Parasitic copepods on tail of Sand eel {Ammodytes tobianus} from Barents sea, Northern Europe

Doug Perrine / Greenland sleeper shark (Somniosus microcephalus) with parasitic copepod (Ommatokoita elongata) attached to eye, and underwater photographer, St. Lawrence River estuary, Canada NB: this shark was wil...

Norbert Wu / Shortfin Mako (Isurus oxyrhynchus) fast and aggressive, copepod parasites trailing from dorsal fin, San Diego, California

David Fleetham / Tricolor parrotfish (Scarus tricolor) supermale sleeping at night protected by a mucus cocoon that it secretes, with parasitic copepod caught in it, Tubbataha Reef, Philippines, Pacific Ocean.

David Fleetham / Parasitic copepods just behind the pectoral fin of Trumpetfish (Aulostomus chinensis), Hawaii, Pacific Ocean.

Tony Wu / Hairy frogfish (Antennarius striatus) male resting, lump on head and abdomen resulting from infection by Parasitic copepod (Sarcotaces pacificus). The female parasite resides within the lump where she...

Tony Wu / Hairy frogfish (Antennarius striatus) male resting, lump on head and abdomen resulting from infection by Parasitic copepod (Sarcotaces pacificus). The female parasite resides within the lump where she...