Fish size themselves up in a mirror to decide if they can win a fight

Cleaner wrasse use their reflection to build a mental image of their body size, which they use to compare themselves to rivals before picking a fight

​Cleaner wrasse use their reflection to build a mental image of their body size, which they use to compare themselves to rivals before picking a fight Cleaner wrasse use their reflection to build a mental image of their body size, which they use to compare themselves to rivals before picking a fight