Hardy, peaceful and beautiful to look at – there’s a lot to love about marine fish. Find out more about how to setup a saltwater aquarium, and care for your new friends with this handy guide.

Saltwater fish care/Marine fish care

Marine fish fact file

Life span – Up to 28 years
Size – Up to 6cm
Diet – Ocean organisms, fish pellets and flakes
Home – Tank – no less than 75 litres

Care and maintenance

Saltwater fish, also known as marine fish, need a very particular environment to stay happy and healthy. Since these fish come straight from the sea, their habitat needs to replicate the ocean as closely as possible in order to keep them vibrant and in good physical condition.

Your saltwater aquarium will need to meet quite specific requirements. To analyse and maintain these levels, you can invest in testing tools at your local Petbarn.

Temperature: Saltwater fish will thrive in water that is between 23 and 28°C.

Salinity: The ocean’s salinity is about 34–37 parts per 1000 units of water. Keep your saltwater fish healthy by replicating this in your aquarium environment.

pH: Your new aquarium will need to maintain a pH level of between 7 and 9.

Setting up

Before introducing new fish to your tank, the water must be cycling for at least one month. The environment needs to have the right pH, ammonia, nitrite, nitrate and salinity levels. It will also need the right water filters, heaters and test kits, which will need to be in place to ensure your saltwater aquarium is perfectly stabilised. Talk to your local Petbarn team member for recommendations.

Create a foundation for your tank with marine substrate, sand and live rock, all found at your local Petbarn. Live rock not only keeps your tank looking colourful, it also shows you whether the aquarium has stabilised and is ready for your fish as it is a living organism. Talk to your local Petbarn team member about what else you could introduce into your tank.


When looking for the best food to give your marine fish it’s important to consider whether they are herbivores, carnivores or omnivores. You will need to determine their dietary requirements and provide food accordingly.

Just as their environment needs to replicate the ocean, their diet needs to be as natural as possible.

Saltwater fish will feed on organisms that are normally found in their natural habitat, such as krill or plankton. Of course, there are specialised fish pellets and flakes that contain the perfect mix of vitamins and nutrients to help your marine fish thrive – find them at your local Petbarn!

A common cause of death for fish is overeating. You need to be aware of the amount of food you provide – depending on how often you feed your fish and how many you have.

Feed your fish at intervals of at least two days to stop them from overeating. Ask your local Petbarn team member what type and amount of food is best for your particular breed of fish.


You will need to clean your aquarium often to ensure your marine fish remain in tiptop condition, and you can find all the aquarium cleaning supplies you need at Petbarn now. Perform water changes once every two weeks by removing one-tenth of your tank’s water, making sure you siphon out the nasties that float to the top as well!

When cleaning your tank and all of the elements inside, the easiest way is to remove each individual component from your tank in sections. Once removed, clean them in a separate bucket to prevent contamination.

Start by cleaning the substrate, taking it and filling the bucket one-third of the way up with clean, fresh water. When you mix the substrate through the water, you’ll notice that any dirt or impurities will float to the top. Repeat these steps for every item in your tank.

While everything is drying you can wipe down the walls of your tank with a clean piece of cloth.

Once you have finished cleaning, replace all of the different elements in your tank and refill it with salt water that you have brought to the correct temperature, then return your fish to their home.

Tip: investing in an algae scraper or magnetic glass cleaner will keep your tank extra clean.


When buying your saltwater fish, make sure to check their fins are healthy and they are swimming properly. Saltwater fish can be prone to internal parasites and worm disease – check their excretion is brown and compact to make sure they don’t have any infections. Be careful to check that they have bright, clear eyes that don’t look swollen or uneven.

Fish can be prone to White Spot, Gold Dust Disease and Tuberculosis. Check your fish at least once a day and look out for any physical changes. Changes in colour, spots, bulging eyes or swelling are signs your fish may have a serious ailment that, if left untreated, could infect the rest. If you notice any of these signs refer to your local Greencross Vets and they can recommend the right fish medications and health supplies you may need.

Fish types – compatibility

To maintain a successful saltwater aquarium, you want your fish to live happily together. While hostile fish may not seem like the biggest issue when giving your new marine fish a comfortable home, incompatible fish can cause stress, disease and injury.

By doing your own research, and with the help of your local Petbarn team member, you will have an insight into what marine fish peacefully coexist in their natural ecosystem.

Some beginner-friendly marine fish species include: tangs, damselfish, firefish, dottyback, blenny fish, watchman goby, butterfly fish, chalk bass, clownfish and mollies. Shop the perfect live fish for your aquarium online or in-store at Petbarn now.

Tip: Check your water regularly to ensure it’s in top condition.

Saltwater fish checklist

Check each item off your saltwater fish supplies list, including the live fish themselves, online or in-store at Petbarn.


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