The Elements of Evolution (43-15-15) False Eyespots

 False Eyespots

The Ambon damselfish is a frequent prey to larger fish. The young are naturally more vulnerable. Clever adaptation has given damselfish fry a better chance of reaching adulthood.

Ambon damsels are a pale yellow, with a distinctive circular black eye toward the top of their tailfin, which fades as a fish matures. Ambon eyes can quickly change during juvenile development. When fry are in a hostile environment, their false dorsal fin eye grows larger, while the display of their real eye shrinks.

The false eye gives a predator a 1st impression that the damselfish is headed in the opposite direction of where it is actually going. This misdirection gives the Ambon 5 times better odds of survival than damselfish which lack the eyespot.