Sober fish led by drunks


Researchers have found that inebriated Zebra danios convince sober fish to follow them about.

Earlier studies have found that a moderate dose of alcohol makes fish more active, while a higher dose has more of a sedative effect and slows them down. But Maurizio Porfiri, an associate professor at the New York University Polytechnic Institute of Engineering, wanted to see how drunk fish would behave when they were placed in an aquarium with sober ones.

Porfiri and his team subjected the fish to three different alcohol concentrations: 0.25%, 0.5%, and 1%.

The study showed that swimming in a high concentration of alcohol made the fish swim faster and become bolder — and when they were placed in alcohol-free water with clearheaded fish, the sober individuals followed the inebriated ones, and even sped up to keep pace.

Porfiri says it's possible that the fishes’ drunk behaviour is perceived as a boldness trait, imparting a high social status.

However, the study also found that the fish exposed to the highest alcohol concentration became sluggish and began to fall behind the rest of the group, so losing their status as leaders.  

Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.

Don't forget that PFK is now available to download on the iPad.