A happy fish is a dead fish

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Hybrid striped bass exposed to the antidepressant fluoxetine (the generic name for Eli Lilly's Prozac) are less interested in food and more prone to unusual behaviour that could compromise its safety, according to a study published in a recent issue of the journal Aquatic Toxicology.

The study by toxicologists at Clemson University Kristen Gaworecki and Stephen Klaine exposed hybrid striped bass (Morone saxatilis x M. chrysops) to elevated levels of fluoxetine (about 1000 times the level normally found in wastewater) and observed the responses of the fish to live prey (fathead minnows, Pimephales promelas) offered as food.

Fluoxetine is increasingly being found in natural waters and is believed to have a number of different negative effects upon fish species.

Picture by Michiel1972 (Creative Commons)

The authors found that the fish exposed to fluoxetine took longer time in between capture of individual prey (suggesting that the treated fish had depressed appetites) and that this response was also dependent on the concentration and time of exposure.

It was also discovered that ...bass exposed to high fluoxetine concentrations were observed maintaining their position at the top of the water surface rather than the bottom of the tank like control bass, sometimes with their dorsal fin out of the water.

They were also noted to maintain a vertical position in the aquaria; these behaviors persisted throughout both the exposure and recovery periods....

The authors postulate that abnormal behaviour of this nature is detrimental to the well being of the fish, making them easy prey for predators.

For more information, see the paper: Gaworecki, KM and SJ Klaine (2008) Behavioral and biochemical responses of hybrid striped bass during and after fluoxetine exposure. Aquatic Toxicology 88, pp. 207"213.