It was once commonplace in UK homes as every child's first pet.

But now goldfish sales have taken a dive, with the number of fish owners falling by half over the past five years.

The number of households with a pet fish is down from 17 per cent in 2012, to just 10 per cent in 2017, Mintel data shows.

The fall coincides with a major rise in people posing with their pets for "pet selfies" to be shared on social media sites like Instagram and Facebook.

But while posing with furry creatures such as cats, dogs and rabbits has become a major craze, fish have failed to make the cut as a selfie-worthy pet of choice.

The slide in fish ownership also came in the wake of a crackdown on funfair or fete stallholders handing out goldfish as prizes to children under 16.

In the past they were widely distributed this way, but now those who do can now be jailed for up to a year under animal protection laws. The same sentence would apply to pet shop keepers who sell animals to under-16s unless an adult is present.

Emma Milne, a TV vet, said: "I’m sure the rise of social media has had an impact on pets from all angles and may well have affected fish numbers while conversely hiking the popularity of other pets.