From garden ponds filled with Koi Carp to the humble goldfish bowl (although goldfish are far happier living in a larger tank) – the UK is a nation of fish lovers.
There are an remarkable five million indoor fish tanks in the UK alone, according to the Pet Food Manufacturers’ Association (PFMA).
That’s about 10 per cent of British households – making fish the third most popular pet after dogs and cats.
It’s a fascinating hobby, particularly for youngsters, and there are few more relaxing activities than watching fish slowly swim around their home.
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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 that will happily live in the corner of your living room.
The first decision to make is whether you are going to pick a freshwater or saltwater tank - saltwater is a little more demanding - before choosing your fish breeds.
One of the most important things to note when choosing a new pet fish for a freshwater tank is whether they are likely to be aggressive - bullying, nipping or even eating their tankmates.
Many fish can co-exist happily with numerous other breeds in so-called community tanks, while others should be kept alone, with other fish of the same breed, or with breeds that are similarly aggressive.
Here are 12 of the most aggressive breeds of colourful tropical fish - caution is recommended.
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5. 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
6. Convict Cichlid
Despite their (relatively) small size, Convict Cichlids are fierce fighters wheo become super-aggressive during breeding - often attacking much larger fish. Their relentless territorial defense mechanism makes them unsuitable for peaceful community tanks. | Canva/Getty Images
7. Betta Fish
Like humans, the majority of aggression in beautiful Betta Fish is confined to the males - giving them their alternative name of Siamese Fighting Fish. Males can become aggressive even if they are able to see a competing Betta Fish in another tank. | Canva/Getty Images
8. 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