bottom feeder

Noun

 * 1) A fish or other aquatic creature that feeds off the bottom of its habitat; a flatfish.
 * 2)  A person who operates amidst or thrives on the unwholesome things in a society; one who takes advantage of the misfortune of others.
 * 1)  A person who operates amidst or thrives on the unwholesome things in a society; one who takes advantage of the misfortune of others.

Translations

 * Finnish:
 * French:
 * German: Bodenbewohner, Grundfisch
 * Spanish: pez de fondo