Rainbowfish are a stunning addition to any freshwater aquarium, known for their shimmering scales and peaceful nature. Native to Australia and parts of New Guinea, these vibrant swimmers are not only beautiful but also hardy—making them a favourite among beginner and experienced aquarists alike. This guide will walk you through everything you need to know about keeping rainbowfish happy and healthy in your Aussie home aquarium.

Origins & Fun Facts

Rainbowfish belong to the family Melanotaeniidae, with most aquarium species falling under the Melanotaenia genus. The name Melanotaenia means “black band” in Greek, a nod to the dark stripe found on many species.

• Shimmering Scales: Their sparkle isn’t from pigment, but from microscopic structures that reflect light—think natural bling.

• Sexual Dimorphism: Males often sport more intense colours, especially when trying to impress the ladies.

• Native Diversity: Australia boasts over 30 native rainbowfish species, many isolated in remote rivers and lakes.

• Conservation Role: Some wild populations are under pressure, so hobbyist breeding plays a vital part in preserving them.

• First Discovery: These stunners were first documented in the 19th century and have been turning heads in the hobby ever since.

Source: ResearchGate

Why Choose Rainbowfish?

Rainbowfish are perfect for those looking to build a lively, colourful tank with minimal fuss. Their peaceful temperament and active nature make them great community fish. Plus, they’re native to Australia, so they’re well-suited to local water conditions.
Not to mention, they’re the aquatic equivalent of a disco ball when the light hits just right.
Top Reasons to Choose Rainbowfish:

• Native to Australia
• Hardy and adaptable
• Peaceful and community-friendly
• Stunning colours that intensify with age and health
• Popular Rainbowfish Species in Australia
• There’s a whole rainbow to choose from! Here are a few species commonly available in Australian aquarium stores:
• Melanotaenia splendida (Eastern Rainbowfish): One of the most common types found in Aussie waters.
• Melanotaenia duboulayi (Crimson-Spotted Rainbowfish): A local favourite known for its reddish hues.
• Melanotaenia praecox (Neon Dwarf Rainbowfish): Small but striking, great for smaller tanks.
• Melanotaenia Trifasciata (from various Australian waterways like Mary River, Howard River, Cato River and much much more) Varying colours with incredible contrast, depending on the Glossolepis incisus (Red Rainbowfish): A bold, fiery species that becomes redder with maturity.

Tank Setup & Size

Rainbowfish love to stretch their fins! They are active swimmers and thrive in longer tanks with open space. A 3-foot tank (around 90cm) is the minimum for a small group, but a 4-foot or larger tank will give them more room to dazzle.

Ideal Tank Setup:

Tank size: Minimum 90cm for small groups; 120cm+ recommended

Water temperature: 24–28°C, pH: 6.5 to 7.8 (remember that fish prefers stability, instead of chasing a pH level, so if your local water is in that range, that would be fine)
Filtration: Strong, as rainbowfish prefer well-oxygenated water. They also like a mid to strong water current, so consider using a wave maker or a power head device and watch them dance and fight against the current. This increases their metabolism and can encourage breeding behaviour. Note: Like us, they need breaks from exercise so either have it turned on for an hour or so or if you have a bigger tank, ensure they can step out of from their swim treadmill to rest.
Substrate: Sand or fine gravel
Plants: Hardy plants like Java fern, Vallisneria, and Anubias
Lighting: Moderate to high to bring out their colours
Tip: Use a tight-fitting lid. Rainbowfish are notorious acrobats and will happily leap for joy—straight out of the tank.

Schooling Behaviour & Tank Mates

Rainbowfish are social butterflies of the freshwater world. They need to be kept in groups of at least six to feel comfortable and show off their best behaviours and colours. Think of them as the fish version of a dance troupe—synchronised and fabulous.
Suitable Tank Mates:

• Corydoras catfish
• Bristlenose plecos
• Tetras (e.g., Rummynose, Lemon, Black Neon)
• Gouramis (peaceful species)
• Livebearers (Platies, Mollies)

Avoid aggressive or fin-nipping species like Tiger Barbs or large cichlids that might rain on the rainbowfish parade.

Feeding Rainbowfish

Rainbowfish are omnivores with a big appetite for variety. A good balance of quality pellets, flakes, and frozen or live food will help them look and feel their best.

Best Food Options:

• High-quality pellets with natural colour enhancers
• Frozen bloodworms, brine shrimp, daphnia
• Live blackworms (occasional treat)
• Blanched veggies like zucchini or spinach (once a week)
• Feed small amounts 1–2 times a day. They’re fast eaters, so keep an eye out to ensure no one misses out on the buffet. We recommend Dymax Colour Plus with added Prebiotic to really promote the natural colouration in fish.

Breeding Rainbowfish in Home Aquariums

Want to raise your own mini rainbows? Breeding rainbowfish is doable at home with the right setup. Most species are egg scatterers and can breed in a community tank, though the fry will have better survival rates in a dedicated breeding setup.
Tips for Breeding Success:

• Use a separate breeding tank with Java moss or spawning mops
• Maintain slightly warmer water (~27°C)
• Feed parents high-protein food
• Remove adults after spawning to protect eggs
• Fry can be fed infusoria or powdered fry food initially, then graduate to baby brine shrimp when they’re ready.

Common Questions from Aussie Fishkeepers

Are rainbowfish aggressive?

No. They may have a bit of a social pecking order but are generally peaceful.
Do rainbowfish jump out of tanks? Yes! They’re Olympic-level jumpers. A secure lid is a must or add some tall aquatic plants like vals that would cover the brim of the water level, but secure lid would be your best bet.

Can I keep rainbowfish with shrimp?

Larger shrimp like Amanos usually do fine, but baby shrimp may become snacks.

Are rainbowfish good for beginners? Absolutely. Their hardiness and cheerful nature make them a top pick.

Where to Buy Rainbowfish in Australia

You can find rainbowfish in most local aquarium stores. At AllFish2u, we stock a rotating and wide selection of healthy rainbow fish, sourced ethically and suitable for community setups. Our staff can help you select the right species and offer setup advice tailored to your space.

Pop in or give us a bell to find out what’s schooling in today or you can check out our weekly updates of rainbowfish right here

Final Thoughts

Rainbowfish are a fantastic choice for Aussie fishkeepers. Their adaptability, ease of care, and colourful display make them an absolute joy. With the right setup and care, these native beauties will thrive and become the centrepiece of your tank.
Whether you’re just starting out or expanding your aquascape, rainbowfish are a vibrant, rewarding choice. If you’re looking for a freshwater fish with flair, these little swimmers are a fin-tastic option.
Happy fishkeeping!