Whether its lovingly-kept garden ponds filled with Koi Carp to the humble goldfish bowl (although goldfish really need a proper tank to be happy and healthy) – Britain is a nation of fish lovers.
The Pet Food Manufacturers’ Association believe there are an amazing five million indoor fish tanks in Britain - that makes them the most popular animal in the country other than the ubiquitous to cats and dogs.
There’s plenty of choice when it comes to adding fish to (carefully set up) home aquariums, with pet shops offering a bewildering range of colourful and interesting finned friends.
Different breeds of fish have very different attributes - some easy to look after some difficult, some top feeders some bottom feeders, some lively and others happy to slink at the bottom of the tank.
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One of the most important things to note when choosing a new pet fish 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 the 26 least, and most, aggressive breeds of popular tropical fish.
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17. 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
18. 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
19. 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
20. 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