sand
-dirt stays above the sand
-good for light reflection
-needs to be stir'd up once in a while
gravel
-dirt hides in between gravel
-good for fish that needs dim lights
-takes twice the time to clean up and vacuuming
-might be swallowed by fishses while feeding
-works best with undergravel filter
bare
-easy maintnance
happy fishkeeping
-dirt stays above the sand
-good for light reflection
-needs to be stir'd up once in a while
gravel
-dirt hides in between gravel
-good for fish that needs dim lights
-takes twice the time to clean up and vacuuming
-might be swallowed by fishses while feeding
-works best with undergravel filter
bare
-easy maintnance
happy fishkeeping