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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9. Pea Puffer
The Pea, or Dwarf, Puffer is one of numerous species of Puffer Fish - and one particularly popular with aquarium owners. Some are tremendously toxic and all tend to display aggression to tank-buddies. Keep them away from other fish though and they make fascinating pets. | Canva/Getty Images
10. Peacock Bass
The Peacock Bass is a fish for serious aquariasts only - needing at least a 150 gallon tank. A predatory species, if they get peckish they'll eat pretty much anything put in front of them, including other Peacock Bass. | Canva/Getty Images
11. Red Devil Cichlid
Not content with being aggressive to other fish, the Red Devil Cichlid is also known for attacking everything from tank decorations to plants. They are tremendously charismatic fish though and a joy to own - just don't expect them to have any finned friends. | Canva/Getty Images
12. Oscar Fish
Yet another species of aggressive cichlid, the Oscar Fish is a natural born bully that will happily eat small fish by the shoalful. If you are going to keep other fish with them they need to be of a similar size and of an equally aggressive nature. | Canva/Getty Images