In his book, Bait Tail Fishing, Al (ALOU) Reinfelder states that at any given time, 90 % of the fish are either be at the top or bottom of the water column.
What is your experience?
Daytime vs. nighttime

On the bottom 90% of the time, day or night. The bigger they get, the closer to 100% you get. This doesn't mean they won't come up for something. Its just an observation as to there the largest levels of large lay laterally lounging. Tongue twister.