From garden ponds filled with Koi Carp to the humble goldfish bowl (although goldfish really need more space to be happy and healthy) – the UK is a nation of fish lovers.
According to the Pet Food Manufacturers’ Association there are an incredible five million indoor fish tanks in Britain - that makes them the third most popular animal to welcome into our homes after cats and dogs.
There’s plenty of choice when it comes to adding fish to (well prepared and correctly set up) home aquariums, with pet shops offering a bewildering range of colourful and interesting finned friends.
But you should be aware that while some fish are placid and happy to live in a ‘community tank’ with a mixture of other species, others are predators that can cause serious issues for other fish.
They can still make great - and fascinating pets - but just need their own space away from potential prey.
Here are 13 of the most aggressive to watch out for.
5. Tiger Barb
Individually small and relatively harmless, Tiger Barbs become highly aggressive in groups. They relentlessly nip fins of slower fish, causing injuries and stress. Their pack aggression makes them notorious bullies and feared by other fish. | Canva/Getty Image
6. Bucktooth Tetra
Most Tetras - like the much-loved Neon Tetra - are chilled and happy-go-lucky fish. The exception is the Bucktooth Tetra, which has the nasty habit of nibbling scales off other fish, leaving them open to potentially-fatal infections. If you want to keep these you'll probably not want any other species of fish in the tank. | Canva/Getty Images
7. Texas Cichlid
The Texas Cichlid is aggressive, territorial, and intolerant of most tankmates - this is a creature not in the market for making fishy-friends. It often attacks competely indiscriminately and without warning, especially when it has breeding on its mind. Its strength and persistence make it difficult to manage in mixed setups. | Canva/Getty Images
8. Jack Dempsey Fish
Originally from Central American countries like Mexico and Honduras, the Jack Dempsey Fish is named after a famous 1920s boxer thanks to its fearsome face and aggressive nature. Best kept alone in a tank, it's also important to provide them with somewhere to hide away. | Canva/Getty Images