Most of us will have had a pet or two as we were growing up - and lucky kids will have had even more.
Many families will have been delighted to win a goldfish as a prize at a funfair, happily putting it in a bowl and feeding it every day after school.
But they could have been guilty of animal cruelty without even knowing it.
Goldfish might get a bad reputation of being boring pets - and having rubbish memories - but they're more clued up than we realise.
In Switzerland, it has been illegal to own one solitary goldfish since 2008, when the country introduced a whole host of animal rights' legislation.
Why? Because fish are actually 'social' creatures. In the sea they swim in shoals, so it makes perfect sense that they would need companions.
The Swiss government believes it is cruel to force them to live in isolation - but it doesn't just apply to fish.
Other social creatures like guinea pigs and budgerigars are also covered by this legislation.
Switzerland even has companies which pair guinea pigs up with partners when the inevitable happens and one of the original couple dies.
While allowing animals to keep each other company makes perfect sense, the country has other bizarre rules regarding pet ownership.
Dog lovers having to take courses before they can own one - and then have practical training, according to techly.com .
If you want just the one cat, you must let it outside so it can see other cats. If it's going to be kept indoors, then you've got to get two.
Looking to purchase a solitary parrot in Switzerland? Forget about it. It'll be considered abuse unless you can get him a friend to talk to.
One thing's for sure, this will certainly make a few Brits feel guilty about their pet-owning habits.
What do you think about these Swiss rules? Have your say in the comments below