* Time of day: They are more active and feed higher in the water column during the day, then move closer to the bottom at night.
* Water temperature: They prefer warmer water and may move deeper in colder conditions.
* Availability of food: They will go where the food is, whether it's near the surface or the bottom.
* Season: During spawning season, they may be found in shallow, weedy areas.
So, bass are not exclusively bottom-dwelling fish, but their diet and behavior often lead them to spend time near the bottom, especially at night or when the water is cold.