Fish And Beer: A Curious Relationship Explored

Fish don't drink, but they can get drunk. A video of a fish gulping down beer from a can in Brazil went viral in 2016, but researchers have been studying the effects of alcohol on fish for years. In 2014, researchers at NYU exposed zebrafish to alcohol and found that they swam faster in a group setting and displayed decreased inhibitory behaviour. Interestingly, the sober fish also swam faster in the presence of a drunk fish, following the intoxicated fish's assertive movements.

Zebrafish exposed to alcohol become more confident and faster

A study led by Maurizio Porfiri, an associate professor of mechanical and aerospace engineering, found that zebrafish exhibit behavioural changes when exposed to alcohol. The study involved letting the zebrafish swim in a solution of ethanol, with concentrations ranging from 0.00% to 1.00% ethanol. After marinating in the solution for five minutes, the zebrafish were dropped into fresh water with a school of sober zebrafish.

The results showed that zebrafish exposed to 0.25% and 0.50% ethanol swam faster and showed little fear or hesitation. They also exhibited signs of leadership, with their assertive movements steering the direction of the entire group. However, zebrafish exposed to 1.00% ethanol lost their leadership skills and lagged behind the other fish.

Another study by Heloysa Araujo-Silva et al. also found that zebrafish exposed to alcohol exhibited increased boldness and responsiveness to a shoal. The study categorised zebrafish into two behavioural profiles: bold and shy, based on their risk-taking behaviour. When exposed to 0.5% alcohol, bold fish showed increased responsiveness to the shoal, while shy fish exhibited decreased shoaling behaviour when exposed to 0.1% and 0.5% alcohol.

These studies suggest that zebrafish exposed to alcohol become more confident and faster, with their behaviour depending on the concentration of alcohol and their individual behavioural profiles.

Drunk fish can double their swimming speed

Fish don't drink beer, but they can get drunk. A study by researchers at NYU exposed zebrafish to various environments of EtOH, or alcohol. The researchers found that the intoxicated fish swam faster in a group setting than they did when observed alone. The untreated fish also behaved differently in the presence of a drunk fish, swimming faster without other noticeable changes in their swimming patterns.

In 2014, a team in New York gave ethanol to a zebrafish and found that when surrounded by other fish, its swimming speed doubled. The fish exposed to the 1.00 percent ethanol solution lost their leadership skills and lagged behind the other fish, seemingly a bit stumbly and slow.

The study also found that alcohol decreased the inhibitory behaviour in fish. Zebrafish, when exposed to a slight buzz of alcohol, threw their inhibitions out the window. They swam faster, and showed little fear or hesitation.

The tipsy fish also showed signs of leadership; its assertive movements steered the direction of the entire group. When the intoxicated fish turned, so did the others. Researchers think this may be because they were influenced by the fish's alcohol-induced boldness, which they might have interpreted as a sign of leadership.

Alcohol decreases the inhibitory behaviour in fish

Alcohol has been shown to decrease the inhibitory behaviour of fish, with studies on zebrafish and Siamese fighting fish showing that exposure to alcohol increases their aggression. A study on zebrafish found that exposure to a 1% ethanol solution decreased their locomotor activity, but they showed a more intense reaction to external stimuli.

Zebrafish exposed to low concentrations of alcohol (0.25% and 0.50% ethanol) were found to swim faster and display little fear or hesitation. They also exhibited signs of leadership, with their assertive movements steering the direction of the entire group. However, fish exposed to a higher concentration of 1.00% ethanol lost their leadership skills and lagged behind the other fish.

Similar to humans, alcohol appears to have a disinhibiting effect on fish, increasing impulsive and risk-taking behaviour. This is supported by animal research, which has demonstrated that alcohol leads to increased aggression, impulsivity, and playfulness.

The mechanism behind alcohol's effect on behaviour may be explained by the alcohol myopia theory, which suggests that alcohol limits cognitive capacity, causing individuals to focus on the most salient environmental cues. This can lead to either disinhibited or inhibited behaviour, depending on the cues present.

Overall, alcohol decreases the inhibitory behaviour of fish, leading to increased aggression, impulsivity, and risk-taking. The specific behavioural responses can vary depending on the species, environmental cues, and alcohol concentration.

Fish exposed to high alcohol concentrations experience sedative effects

Alcohol produces both stimulant and sedative effects in humans. Fish exposed to high alcohol concentrations experience sedative effects.

Zebrafish, in particular, have been found to exhibit a lot of similarities to humans in terms of development, behaviour, and genetics. In a study, researchers exposed zebrafish to a solution of ethanol with concentrations ranging from 0.00, 0.25, 0.50, and 1.00 percent ethanol. The fish were then dropped into fresh water with a school of sober fish, and their responses were monitored.

The study found that zebrafish exposed to ethanol concentrations of 0.25 percent and 0.50 percent exhibited reduced inhibitions, swimming faster, and showing little fear or hesitation. They also displayed signs of leadership, with their assertive movements influencing the direction of the entire group.

However, when exposed to a higher concentration of 1.00 percent ethanol, the zebrafish lost their leadership skills and lagged behind the other fish, appearing sluggish and slow. This finding highlights the sedative effects of high alcohol concentrations on fish, similar to the effects observed in humans.

In humans, alcohol acts as a central nervous system depressant, decreasing electrical activity in the brain. It produces stimulant and sedative effects, with the sedative effects typically occurring during the descending limb of the blood alcohol concentration curve. The sedative effects of alcohol include decreased social inhibition, sedation, cognitive impairment, and motor slowing.

The sedative effects of alcohol are particularly notable in light drinkers, who experience significant increases in sedation after consuming intoxicating doses of alcohol. In contrast, heavy drinkers tend to exhibit lower sedative responses to alcohol, which may contribute to their propensity for alcohol misuse.

Fish have a lot of similarities to humans when it comes to genetics and behaviour

Fish and humans share a lot of similarities when it comes to genetics and behaviour.

Zebrafish, in particular, have been found to have a lot of similarities to humans in terms of development, behaviour, and genetics. Zebrafish are argued to offer translationally relevant discoveries, meaning that findings made with zebrafish can help us understand the biological functioning and malfunctioning of other species, including our own. This is because zebrafish are thought to possess evolutionarily conserved features. In other words, zebrafish and humans have been evolving separately for only 0.4 billion years, whereas these two species share about 3.1 billion years of common biological evolution.

For example, at the genetic level, the nucleotide sequence of fish and human genes are similar enough to allow for the identification of human orthologs with high confidence based on fish sequences and vice versa. This suggests that there are a large number of biological features that humans share with zebrafish. Additionally, the lateral pallium of cyprinids (the family of zebrafish) has been found to be homologous to the mammalian hippocampus, with both structures involved in complex forms of learning.

When it comes to behaviour, zebrafish and humans exhibit similar social behaviours. Zebrafish form shoals, aggregates of individuals in which fish stay close to one another, while humans organize themselves into families, tribes, sports clubs, and nations. Additionally, a study on rainbow trout found that some fish are routine-bound creatures of habit, while others are better able to improvise, similar to humans. This suggests that fish, like humans, can be divided into two personality types: proactive and reactive. Proactive fish are more aggressive and assertive, but also more fixed in their ways, while reactive fish are less aggressive and more timid, but more open and flexible, and able to adapt more easily.

In summary, fish and humans share a number of similarities in terms of genetics and behaviour, with zebrafish being a particularly well-studied species in this regard. These similarities can provide valuable insights into the biological functioning and malfunctioning of our own species.

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