Our Complete Guide to Looking After Your Freshwater Fish

By: Pet City   On: 22 November 2022 

Having an aquarium with fish is relaxing and can improve your quality of life. While you might hesitate at a full-on tropical fish tank, you can still enjoy the benefits of fish with a freshwater fish tank. Arguably easier to set up and maintain when compared to a saltwater, tropical tank, a freshwater fish tank can be set up for much less cost, and have a much lower maintenance schedule. Please read our guide for looking after your fresh fish tank, click through to our freshwater aquarium supplies, and start your aquarium today.

What Are Freshwater Fish? 

Freshwater fish are those that spend the majority of their lives in rivers or lakes, with a salinity level of less than 1.05%. Over 40% of fish species are freshwater fish.


Common Species of Freshwater Fish for Aquariums

Not all freshwater fish are suitable for an aquarium, of course. Some of the best freshwater fish for your aquarium include:

  • Guppy - a popular breed and a cute fish with a fan tail, which originates from South America. They’re also known as Rainbow Fish or Million Fish. They live well in a communal tank and love to swim around.
  • Platy Fish - an easy fish for beginners, they’re a chill little fish who get along with everyone.
  • Angel Fish - a strikingly beautiful freshwater fish that would not look out of place on a reef. Slow and stately swimmers, are omnivorous and can eat worms or flakes. Beware that if they get too big, they might eat smaller fish.
  • Tetras- small, brightly coloured fish which, again, are great for beginner aquariums. They're small and shiny, look great in schools, and are long-living fish- up to 8 years.
  • Killifish - a beautiful and very popular fish for your freshwater tank. There are many different species, and all are brightly coloured. They get along with other fish, but males of the same species could get aggressive with each other.


What Do You Need to Look After Your Freshwater Fish?

There are some essential things you need when setting up your fish tank besides fish. Pet City has all you need to get started, and maintain your fish tank, right here.

  1. Water Conditioner. This helps innoculate your fish tank against the ammonia produced by fish waste. Ammonia is toxic to freshwater fish, and a build-up will kill them.
  2. Tank filter. These not only oxygenate water through movement, but they can also provide three types of filtration- mechanical, chemical and biological. 
    1. Mechanical filtration - water passes through a filtration pad.
    2. Chemical filtration - water flows through activated carbon, removing toxins.
    3. Biological filtration- water flows through a medium that is colonised with healthy bacteria, breaking down ammonia.
  3. Tank Heater. While tropical fish need a warm tank, you can’t just have your freshwater fish swimming in a tank at ‘room temperature’. A temperature at or just below 22 degrees is ideal for freshwater fish.
  4. Circulation Pump. This helps keep the water oxygenated for your fish, pushing heated water around the tank for an even temperature.
  5. Substrate. These are the rocks and sand at the bottom of your tank. Good for aesthetics, it is also a place where good bacteria can grow to help keep your tank healthy. You can have a variety of colourful gravel and stone. If you want real plants to grow in your tank, your substrate needs to be bioactive.
  6. Lighting. Lighting can help keep your tank warm. It can also help you see all your wonderful fish. We don’t recommend keeping your tank near a window, as sunlight can promote the growth of algae. Choose the lights that fit your tank aesthetic. LED lighting, while more expensive, last longer and use less power than fluorescent bulbs.
  7. Water Testing. Test strips, or chemical kits to examine your water are used to test the water for levels of ammonia, nitrate and nitrite. They measure the pH level of your water. Ideally, in your tank, nitrite should be undetectable, nitrate levels should be very low, and pH should be as close to neutral as possible.


How to Set Up Your Fresh Water Fish Tank

  • Once you have bought your fish tank home, the first step is to decide where to put it. Don’t place it in direct sunlight, as this can promote the growth of algae. Try not to place it near heating or cooling, as this can change the conditions of the fish tank. You want to control the temperature of the tank for the health of the fish.
  • Wash and rinse all your gravel and ornaments in hot water. Don’t use chemical cleaners or soap; you’re trying to wash those off. Add the gravel to the tank slowly, don’t pour it in harshly, as it might damage the bottom of the tank.
  • Fill your tank slowly with tap water. A hose is good. Don’t pour the water in quickly. Slow pour minimises dust and dirt, making your water cloudy.
  • Once the water is in, you can turn on any electrical accessories you’ve bought. Doing so before the water could damage them.
  • Add in any water treatments you have.
  • Let the above 2 stages sink in. Let the filters work, and let the water become conditioned. This can take a few weeks. We know you’re super keen to see fish swimming around, but if you don’t prepare your tank properly, they’ll have a real hard time of it.
  • Test your water for the right levels of nitrite, nitrate and ammonia. Once you’re happy with the levels, slowly introduce your fish, a few at a time. Dumping 20 fish into the tank might overload the system and freak the fish out.

For more tips on setting up your aquarium and where to buy some of the equipment, check out our freshwater aquarium page.

What Should You Feed Your Freshwater Aquarium Fish?

Before we tell you what food to feed your fish, we need to say that you don’t want to overfeed your fish. A general rule is to only feed your fish as much as they can eat in 2 minutes. Any more and the food will not be eaten, and will rot on the floor of your aquarium.

  • Fish flakes are the most popular kind of fish food. 2 or 3 flakes per fish to gain a measure of their feeding habits. Fish flakes start floating on the top, so they’re ideal for fishies who like to swim around.
  • Mid-tank swimmers and those fish who hang out at the bottom of the aquarium can go for some fish pellets. They sink slowly and last longer on the bottom of the tank than flakes.
  • Tablets can be stuck to the inside of your tank and can be used to feed crustaceans, snails, or other feeders that can stick to the side of your tank. Other fish can also come along and have a nibble.

Find the perfect food to feed your fish, right here with Pet City 

How Often Should You Feed Your Fish?

You can feed your fish 2 or 3 times a day, but only a small amount, enough food that they can eat in around 2 minutes.

If you notice your fish not eating that often, you can lessen the number of times you feed them. Perhaps they’re not hungry.

Keeping Your Freshwater Fish Healthy

Once you’ve set up your tank, let it acclimatise for a month, and you’ve added your fish, how do you keep them healthy and swimming?


pH Levels

Maintaining the ph levels of your fish tank is key. Too acidic or basic, and your fish can get sick. For freshwater fish, it’s best to maintain a pH level between 6.6 and 6.8.

The natural way to lower a pH level is through the use of peat moss or driftwood. You can also use a Carbon Dioxide reactor.


Correct Water Temperature

The ideal water temperature for freshwater fish is between 23-27 degrees celsius. This is why we say don’t put fish tanks near windows with sunlight or your heater or air conditioner. These can radically alter the temperature of the water.

If the water is too warm, the fish become more active and require more oxygen. However, warmer water holds less oxygen, so they can suffocate.

If the water temperature is too cold, your fish will become sluggish with little energy.


Change the water regularly

Even with the best filters in the business, changing about 25% of your water every month helps to stabilise the nitrate levels in your tank, and you remove random debris and waste products.


Clean the glass

Aglage levels will build up, so scraping and cleaning the glass not only helps with the health of the tank but can prevent fungus and other nasties from infecting your fish.

Pet City has a range of products to help with the health of your fish. Check out our range, add to your cart, and let's go!

Our Top 5 Tips For Looking After Your Freshwater Fish

Are you ready to bring some colourful fishy friends into your life? Let’s review the main points for you so you’re up to speed.


Keep Your Fish Tank Maintenance Up to Date

Have a diary or a plan clearly in view for maintaining the health of your fish. Include cleaning times, replacing the water, checking on the equipment and more.


Create a Feeding Schedule

Much like people, animals enjoy a regular feeding regime. Despite the urban myths, fish do have a good memory and will enjoy regular meal times, just like you.


Keep an Eye on Your Fish

Enjoy your fish, but look out for any strange behaviour. Are they swimming around sluggishly? Are they aggressive toward each other? Are they floating more than swimming? If something seems off, get in touch with your vet.


Keep Tank Water at the Right Temperature

Keep your tank away from air conditioning and heating and away from direct sunlight. Maintain the proper temperature - between 23 and 27 degrees Celsius. Check your aquarium heater if something seems amiss.


Change The Water Regularly

Once a month, change at least 25% of the water. This helps keep your tank healthy by removing debris and waste that can't be filtered, and it helps maintain the nitrate levels of your tank.


Shop Freshwater Fish Supplies at Pet City

For all your freshwater fish supplies, Pet City can help you out. Food and water treatments, heating and lighting for your fish tank, and we have actual fish tanks to start you on your maritime adventures. Drop by our website, or drop into our Brisbane store and become a Pet City VIP today!