30/08/2024
A well-balanced community aquarium will see fishes swimming in all layers of the water column.
Fishes such as the livebearers have evolved to feed at the water's surface and their mouths are upturned (or superior), enabling them to continue to swim in a horizontal plane and keep their eyes monitoring their surroundings.
Conversely, many bottom-feeding omnivores such as loaches and catfishes have an ‘inferior’ mouth that is facing the substrate which similarly allows bottom-feeding without adopting a posture that would mean reduced vigilance for surrounding predators.
The majority of fishes have a ‘terminal’ mouth positioned in the middle of the snout allowing them to effectively feed in the midwater. When planning a community aquarium seek to have fishes of all three types to ensure movement in all layers of the tank.