umm..well fish :p lots of things live in the ocean such as whales,sharks,squids,octopus,shrimp,snails,crabs,oysters,coral,eels, ect. their still are lots of other species that hadn't even been...
Detritivores usually live in soil containing decomposing organic matter, but they can also live in marine ecosystems. For the most part scavengers aren't included as detritus feeders.