Alex Mustard / Nudibranch (Nembrotha cristata) climbing on a Tunicate (Polycarpa aurata) at night. This species of seaslug feeds on seasquirts. A tiny cyclopoid copepod swimming past. Yillet Yecil, Yillet Islands, M...

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 / Salmon shark (Lamna ditropis) female with mating scars and copepod parasites trailing from fins, Port Fidalgo, Prince William Sound, Alaska, USA. Digital composite

Doug Perrine / Salmon shark (Lamna ditropis) female with mating scar on side and copepod parasites streaming from fins, Port Fidalgo, Prince William Sound, Alaska, USA

Solvin Zankl / Marine Planktonic Copepod {Gaussia princeps} female, deepsea, Atlantic ocean

Solvin Zankl / Deepsea marine planktonic Copepod {Euchirella sp} Atlantic ocean

Solvin Zankl / Deepsea marine planktonic Copepod (Sapphirina sali) Atlantic ocean, Digital focus stacking

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

Nick Hawkins / Live copepod (Calanus finmarchius) isolated in a single water drop and displayed on a microscope slide. Photographed at the Bedford Institute of Oceanography, in Halifax, Nova Scotia, Canada.

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.