Tyrannochromis macrostoma (Regan), a haplochromine
cichlid fish endemic to Lake Malawi, Africa, exhibits reverse
countershading. It attacks potential prey fishes from an upright,
sideways (90 degrees rotation from an upright position), or upside-down
(180 degrees rotation from an upright position) positions. Seventy
percent of its attacks are from a sideways position. Whenever it was
observed attacking from an upside-down position, its prey was
stationed below the attacker. When attacking from a sideways position,
its prey was below the attacker 25% of the time and on the same plane 75%
of the time. When attacking from a normal position, its prey was below
the T. macrostoma 82% of the time and on the same plane 18% of the
time. Data presented herein lend credence to the self-shadow concealment
explanation for the selection of countershading. Tyrannochromis
nigriventer Eccles, a closely related species, does not display
reverse countershading but occasionally attacks from an upside-down
position.