Why your goldfish might be able to spot you in a crowd (2024)

He may have a fondness for swimming in circles. But beyond his glassy-eyed stare, your pet goldfish may have hidden depths.

Oxford University scientists have shown for the first time that fish are capable of remembering and recognising human faces.

They are also highly accurate at it – easily picking out a familiar face from up to 44 strange ones.

The research was done on archerfish, a silver and black tropical species, popular in aquaria.

However, researcher Cait Newport said it is possible the skill extends to other species, meaning pet goldfish may remember their owners.

To make the find, Dr Newport capitalised on the archerfish’s ability to spit out jets of water with such force that prey is knocked off overhanging branches and into the water.

For the study, a computer monitor was placed above the aquarium and the fish were shown two different human faces.

They were then trained to spit at one of the two faces – and given a food pellet each time they were on target.

Once Dr Newport was satisfied they had had learned to focus on one of the faces, she started to them dozens of new pairs of faces.

Each pair contained the familiar face and one strange one and the familiar face was moved around the screen, to ensure the fish weren’t simply spitting in a direction they had grown to like.

The four fish accurately picked out the familiar face more often than not.

Dr Newport then repeated the experiment, changing the coloured head shots for black and white ones, in which the all the heads had been cropped to all be the same shape.

Despite the lack of colour and shape making the task harder, the fish still recognised the familiar face, with the brainiest specimen spitting at it 86 per cent of the time.

Dr Newport said: ‘Being able to distinguish between a large number of human faces is a surprisingly difficult task, mainly due to the fact that all human faces share the same basic features.

‘All faces have two eyes above a nose and mouth, therefore to tell people apart we must be able to identify subtle differences in their features.

‘If you consider the similarities in appearance between some family members, this task can be very difficult indeed.

‘It has been hypothesized that this task is so difficult that it can only be accomplished by primates, which have a large and complex brain.’

Writing in the journal Scientific Reports, she said that the feat is made all the more impressive by the fact that fish lack the complex brain circuitry we use to distinguish faces.

It seems they are adapting the techniques they use to distinguish friend from foe in murky underwater conditions.

Dr Newport said it is possible that other fish, such as goldfish, also have such a keen eye.

She said: ‘For your pet fish to recognise you, they would likely have to recognise your face when you are moving and you are presenting different angles of your face to them and while your facial expression is changing.

‘These small differences actually make recognition significantly more difficult to the point that it can be challenging even for computers to do.

‘We didn’t explicitly test if fish can do this more complex task so I can’t say for sure, however, I think our results suggest it might be possible.

‘I know that when new people walk into my laboratory aquariums the fish can get a little bit shy but when I walk in they all start spitting jets of water at me!So you never know.’