GRAVEL
Benefits
Gravel allows water to flow through it, preventing anaerobic "dead zones"
Many colours to choose from
Many sizes and shapes
Easy To clean with gravel cleaners
Wont get blown around by filter
Wont need to be cleaned before adding
Crushed coral for fish
Disadvantage
Food can fall beyond the reach of the fish and rot
Some plants wont root
Can hurt fish if sharp and wear away barbels on catfish like corys
Can be eaten
Looks dirty when algae grows on it
SAND
Benefits
Planting is usually easier in sand
Fish like
corydoras prefer it
Burrowing fish
Many colours
Looks nicer
Coral sand
looks cleaner with fish turning it over
Disadvantage
Anaerobic dead spots
Can be hard to clean
Will need to be cleaned when before adding
Can be blown around, looks messy and get into filter
Shows up dirt more
Can become compacted
can be hard to
plant small plants in
Cant use undergravel filters
Which one?
Depends on plants, equipment and personal choice