Upside down catfish

An upside-down catfish swimming along belly up. Image taken at the California Academy of Sciences.

These fish will often be found relaxing and swimming with their belly’s upward and their dorsal fin pointing downward. And so the question of the day is… Why? Well one thought has to do with the food that these fish eat, such as algae off of floating logs and under leaves and branches and insects floating along the surface of the water. Rather than flipping over every time they are getting a meal, they eventually evolved to just stay upside-down.

upside-down catfish

An upside-down catfish using a leaf to anchor itself and rest. Image taken at the California Academy of Sciences.

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