Best Beginner Freshwater Fish in Australia – Your Complete Guide

Setting up a beginner-friendly aquarium

Before rushing out to buy fish, set yourself up for success with the right tank and gear. Bigger is better for beginners – I learned that a 20-litre starter tank is doable, but a 50-litre tank is much easier to keep stable. More water dilutes waste and gives fish room to swim.

Choose a spot at home away from direct sun (to avoid overheating or algae blooms) and make sure you have a sturdy stand. Essential equipment includes a filter (to keep water clean and oxygenated) and a heater for tropical species. In many Aussie climates, even indoor temperatures can drop at night, so a heater helps maintain consistency. If you opt for goldfish or other cold-water fish, you might skip the heater, but you’ll still need good filtration – goldfish are cute but notoriously messy!

Setting up an aquarium does come with some costs. The tank, filter, heater, lights, and test kits all add up, but they’re a one-time investment in your pet’s welfare. Ongoing expenses like electricity (to run that filter and heater), replacement filter media, water conditioner, and fish food are relatively small but worth noting.

Also consider practical things: I keep a lid on my tank because Pixel would love to go “fishing” if she could. A cover also stops fish from jumping out and keeps dust out of the water (and keeps Pixel from jumping in!). Don’t forget to treat tap water (chlorine in our tap water will harm fish unless you use a water conditioner).

A bit of prep work – like running the tank with the filter for a week and adding beneficial bacteria – can prevent the classic beginner heartbreak of fish dying from “new tank syndrome.” Take it from me: patience pays off when starting an aquarium!

Popular beginner freshwater fish in Australia

When it comes to choosing the best fish for beginners, Australia has plenty of options available at local pet shops. The key is to pick species that are hardy, easygoing, and compatible with our tap water and climate. Here are some top beginner-friendly fish I’ve kept (or considered) in my own tank, along with their pros and cons.

Goldfish (cold-water classics)

Goldfish are the iconic starter fish – hardy, curious, and surprisingly personable. They don’t need heated water (they’re comfy around 20 °C), which is great if you live in a warm area or don’t want to manage a heater. A few words of caution, though: goldfish might start small, but they can grow to 15+ cm and live for over 10 years if well cared for.

That cute little comet or fantail will eventually need a spacious tank (at least 50 L per fish, ideally more) and a strong filter. I learned quickly that goldfish produce a lot of waste, so without good filtration their water gets dirty fast.

On the plus side, they’re very forgiving of beginner mistakes in water quality compared to delicate tropical fish. They’ll happily beg for food and can even recognise you over time! Just avoid the old-school bowl – goldfish in bowls will stunt and suffer (they really do best in a proper tank). If you have limited space or want a cold-water fish that stays small, consider White Cloud Mountain Minnows as well – they’re another hardy species that can thrive at room temperature.

Guppies, platies and mollies (livebearers)

Livebearers like guppies, platies, and mollies are often my go-to recommendation for new fishkeepers. These tropical freshwater fish are small (usually 5–6 cm max), vibrant in colour, and pretty tough when it comes to water conditions. Guppies in particular breed like crazy – a pro or con depending on whether you want baby fish! (If you keep males and females together, be prepared for fry).

Platies and mollies are similar in care: they all prefer warm water (~24–26 °C with a heater), need a modest tank (a group of five can do well in about 40–50 L), and love a bit of plant cover to explore. I appreciate that livebearers are active but generally peaceful community fish. They’ll get along with other non-aggressive species and their constant poking around the tank looking for food is fun to watch.

One thing to keep in mind is not to overcrowd – more fish means more waste. Start with a small group and see how the tank ecosystem handles it. Otherwise, these fish are low-fuss: feed them a good flake or pellet, keep the water filtered, and they’ll reward you with their bright colours (some of my guppies look like tiny neon rainbows) and playful behavior.

Betta (Siamese fighting fish)

The Siamese fighting fish, or betta, is a popular choice for beginners – and for good reason. Bettas are absolutely gorgeous, with long flowing fins and striking colours (my friend’s betta looks like a miniature royal blue dragon). They have a reputation for being able to live in small bowls, but in truth a betta will thrive in a filtered, heated tank around 20 L or more.

A single male betta is a great “solo” pet fish; you don’t have to worry about finding companions (in fact, males will fight if housed together, and they may nip at other fish with fancy fins).

Bettas are tropical, so they need warm water and a heater to stay around 25 °C. They also prefer gentle water flow – in my tank I made sure to baffle the filter output so the current doesn’t toss my betta around. On the upside, bettas breathe surface air thanks to a special organ, which means they handle lower oxygen conditions well (they’ll still appreciate a filter, though, to keep water clean).

Despite pet shop displays, a tiny jar or unheated bowl is not a humane long-term home for these beauties.

Their personalities are a lot of fun: they will greet you every morning, zipping up to the glass expecting food. Treat them to a proper setup and they’re actually one of the easier fish to keep.

Small schooling fish (tetras & danios)

If you prefer a lively community of little fish, tetras and danios are fantastic beginner options. Neon tetras are a classic: tiny (about 3 cm), with glowing blue-red stripes, they look stunning moving as a school. They’re peaceful and do well in groups of six or more. Neons are a bit sensitive to water quality, so I’d suggest adding them after your tank has been running smoothly for a few weeks – but once settled, they’re straightforward to care for in a heated, filtered tank (around 24 °C).

On the other hand, zebra danios are like the hardy scouts of the aquarium world. These striped silver fish are extremely tough and adaptable; they tolerate a range of temperatures (18–26 °C), which means they won’t mind if your heater is a tad off or if you live in a cooler part of Australia. Danios are very active swimmers and love to dart around, so give them space and a lid (they can jump!).

Both tetras and danios are community-friendly, getting along with other non-aggressive fish. A mix of these in a 50 L tank can create a vibrant, moving tapestry of fish. Just remember that “schooling” means they feel safest in numbers – a singleton tetra will be stressed, so always plan to have a small group rather than a lone fish.

Caring for your fish and tank

Once you’ve got your fish swimming in their new home, a bit of regular maintenance will keep things running smoothly. Daily, just enjoy watching them and do a quick check: are the fish active and eating? Is the filter running and the water clear? Feed only small amounts that your fish can eat within a minute or two. Overfeeding is a common rookie mistake – excess food just rots and messes up the water.

I like to feed my fish once or twice a day in tiny portions; if any food is left floating after 5 minutes, I scoop it out. Also, keep an eye on the water temperature. Tropical species will get stressed if it swings too much. Australia’s summer heat can be intense, so I even set up a little smart thermometer that alerts my phone if the tank water goes above 28 °C or below 22 °C. (Yes, that’s me being a tech nerd, but it gives peace of mind!). In winter, make sure the heater is doing its job – in cooler southern regions, a tank can drop below comfortable range without heating.

Beyond feeding and watching, the big task is keeping water clean. Fish live in their toilet, so to speak, so you’ll need to perform weekly partial water changes. This means siphoning out about 20% of the tank water (along with any gunk in the gravel) and replacing it with fresh, dechlorinated water. Doing a 20% change each week prevents waste chemicals from building up and keeps the environment healthy. It’s not as daunting as it sounds – for my tank, I swap out about a bucket’s worth of water weekly, which takes maybe 15 minutes. I use a gravel vacuum to clean the substrate at the same time. Don’t forget to add water conditioner to tap water to neutralise chlorine and chloramine before pouring it in.

Every month or so, rinse out the filter sponge or media in old tank water (not under the tap) to clear trapped debris but preserve the good bacteria.

A healthy colony of beneficial bacteria in the filter is crucial; it’s what breaks down toxic ammonia from fish waste into less harmful forms. If you ever notice your fish gasping at the surface or acting lethargic, test the water – it’s often an issue with water quality. Keeping up with routine water changes, not overstocking the tank, and having a decent filter will prevent most of these problems.

Lastly, be a responsible fish owner. If a fish gets sick, you may need to quarantine it or treat the water with medication (aquarium shops and vets can advise on common diseases like ick or fungus). And if you ever find yourself unable to care for your fish, never release them into local rivers or ponds – in Australia, released pet fish like goldfish can turn into invasive pests that harm native wildlife. Instead, reach out to a local aquarium club or even a friend who might adopt them. Fortunately, with proper planning, your beginner fish should thrive and give you years of enjoyment. There’s nothing quite like kicking back on the couch, watching the serene dance of fish through the tank glass – it’s my daily relaxation ritual, and even Pixel sits contently by my side, mesmerised by our little aquatic world.