Perhaps the most spectacularly colourful variety of fish you could keep in an aquarium, marine fish are quite challenging to have as pets. Take a look at the information below and see if you’d be a suitable marine fish tank owner.


Marine fish tanks have a very specific ecosystem – you’ll need to dedicate some time to researching and choosing the correct tank, the right fish and how you should maintain it before you can even start shopping, so bear in mind that marine fish require a high level of dedication in order to thrive.

There’s a rather extensive list of specialised equipment that you’ll need to buy if you’re thinking of keeping marine fish. You’ll need to research the specific needs of each species, but some of the specialist items you’ll need include:

  • a filter and skimmer to keep your marine tank’s water free from waste
  • the appropriate lights – marine tanks need a brighter light than freshwater tanks due to the differences in the fish’s natural habitat
  • a heater, cooler and thermometer – despite the warmer temperatures needed for a marine fish tank, they can be prone to overheating, so these three items are important for keeping the temperature constant
  • saltwater and a hydrometer – this will monitor the salt levels of your tank
  • a powerhead or pump to ensure the water is always moving, as it would in marine fish’s natural home.

The type of marine fish food you need to provide will depend on whether you have carnivores or herbivores in your tank. Herbivores will eat foods such as algae that grows in the tank, seaweed, or fish food flakes made for herbivores. Carnivores will prefer a diet of shrimp, krill or fish flakes made for carnivores. You can find out more about the different types of fish food in our guide.


If you manage to master the art of keeping marine fish, then they can live for around ten years or more.


As well as their specific lifestyle requirements, it’s important to remember that keeping marine fish is likely to cost you a fair bit more than tropical or coldwater fish. You’ll also need to be able to dedicate time to checking and maintaining your tank pretty much every day, including a clean every week. So if you’re often out of the house for long periods, this may not be the best option for you.