organisms that live off other organisms?

Answer 1

Politicians and clergymen.

Are you looking for specific examples like mosquito's, leeches, tapeworms, ticks, lice?

There are a lot of parasitic animals, plants and fungi.

Answer 2

the little fish that suck on and clean sharks, i forget what they name them but you can google that. The birds that pick at stuff between crocodile and alligator teeth, that kind of stuff, maybe parasites, like tapeworms, and the such are what your looking for.

Answer 3

parasite

Answer 4

consumers