There is some variations of sinking feed.

Many believe that any given fish is more likely to take to a sinking feed as it resembles the path of other food sources. Also meaning that we can't see if the feed is taken in many situations.


Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."