remora

 
Pronunciation: /ˈrɛmərə/

noun

  • a slender marine fish which attaches itself to large fish by means of a sucker on top of the head. It generally feeds on the host’s external parasites. Also called shark-sucker, suckerfish.
    • Family Echeneidae: several genera and species, in particular the widespread Remora remora

Origin:

mid 16th century: from Latin, literally 'hindrance', from re- 'back' + mora 'delay' (because of the former belief that the fish slowed down ships)