Fish Like To Have Fun, Too, Study Shows

Researchers at the University of Tennessee in Knoxville have discovered that fish like to have a bit of fun, too. According to recent findings published in the journal Ethology, life is simply not just about work.

"Play is repeated behavior that is incompletely functional in the context or at the age in which it is performed and is initiated voluntarily when the animal or person is in a relaxed or low-stress setting," said researchers, in a news release. 

For the study, they discovered that the fish species cichlid actually play together.

After filming three male fish individually over the course of two years, they found that the fish seemed to repeatedly "attack" a bottom-weighted thermometer. Furthermore, they noticed that the presence or absence of food within the aquarium resulted in no effect on the frequency fish struck the bottom-weighted thermometer.

Researchers concluded that they believe that this type of behavior helps to satisfy their criteria for "play."

"The quick righting response seemed the primary stimulus factor that maintained the behavior," they concluded. "We have observed octopus doing this with balls by pulling them underwater and watching them pop back up again. This reactive feature is common in toys used for children and companion animals."