Did you know that goldfish can make their own alcohol?

Did you know that goldfish can make their own alcohol?

Like many people, my first childhood pet came in the form of a goldfish. I called her Mango, and - if my memory serves correctly - she lived to the ripe old age of two months.

During her brief time on this mortal plane, Mango didn't really do much. She ate a bit, swam a bit, and occasionally hid in the tacky little stone castle at the bottom of her bowl. At the time, I thought she was just the type of animal to prefer a quiet life.

Now, however, I'm starting to suspect that she was actually drunk off her tiny fins.

Credit: Getty Images

A new study in the journal Scientific Reports has found that goldfish, along with the crucian carp, have the capability to produce their own alcohol.  And by that, I don't mean that they're secretly brewing moonshine in that one murky corner of the tank (as impressive as that would be) but rather that their bodies have biologically evolved to convert lactic acid to ethanol.

It's actually been known for a while that they can do this but, until now, nobody knew how. The study explains that goldfish "depend on the ability of their skeletal muscles to convert anaerobically produced lactic acid into ethanol, which then diffuses across their gills into the surrounding water", which is unbelievably badass when you think about it.

Far from being just a cool party trick, however, this process is actually vital to the fish's survival. When living in low-oxygen environments such as frozen ponds or lakes, carp and goldfish can experience a buildup of lactic acid (something which also happens in humans, and is the cause of muscle pain while exercising), which can be lethal to them. The production of ethanol allows them to carry on swimming, even in oxygen-free water.

Crucian Carp Credit: Getty Images

Genetic analysis shows that the proteins that allow for this process to happen emerged in a common ancestor of the goldfish and the crucian carp approximately eight million years ago - meaning that fish have been getting drunk for millennia before human beings even existed.

Dr Michael Berenbrink, a scientist at the University of Liverpool who was involved in the study, explains that the "blood alcohol concentrations in crucian carp can reach more than 50 mg per 100 millilitres," which is actually above the drink drive limit.

It's no wonder, then, that goldfish are such hardy creatures. Of course, my own experience with young Mango was short-lived, but she seems to have been an anomaly. In fact, the average lifespan of a goldfish is between five and 10 years, but they have been known to live to over 40 years of age.

People enjoying a drink Credit: Getty Images

After this discovery, I'm quite excited to see what else we'll find out about the natural world. Maybe there's some kind of eel out there that produces its own type of stimulant, or an undiscovered insect that has psychedelic blood. Or, better yet, maybe we'll find out that humans have this same ability embedded in some latent gene - and we can experience a relaxing high after a workout, rather than the pain of a lactic acid build-up. It would give a whole new meaning to the phrase, 'drinks like a fish'.