bottom-feeder

Noun

bottom feeder (plural bottom feeders)

1. A fish or other aquatic creature that feeds off the bottom of its habitat; a flatfish.
   • The Apristurus genus, the second-most diverse group of sharks that counts about 40 species, is commonly known as the ghost or demon catshark. […] The sharks are bottom feeders and have elongated catlike eyes.2023 May 12, Lauren McCarthy, “‘A Bit Spooky’: The New Shark Species With Bright, White Eyes”, in The New York Times

   Synonyms:

   bottom dweller, bottom liver

2. (broadly, derogatory, figuratively, informal) A person who operates amidst or thrives on the unwholesome things in a society; one who takes advantage of the misfortune of others.
   • “[T]he rise of Facebook, Twitter and other social media has made it harder to control the flow of information, thus making it easier for bottom-feeders to bully witnesses.” […] Officials are still trying to identify the bottom-feeder behind that account.2013 November 16, Christian Dem, “Bottom-feeders using social media to intimidate witnesses”, in The Daily Kos, NC, archived from the original on 14 Dec 2013