Pick the look, then check the basics. Allow 20 litres or more for a betta, 50 or more for goldfish, and 40 or more for a betta with tank mates. Cover about half the tank in plants or decor, and use only safe materials in the water.
These fish tank ideas are grouped by theme, so you can pick a look and then check it fits your space, your fish and your budget of effort. A tank that photographs well still has to work: the right litres, safe decor and fish that suit each other. Each idea below says what it needs before you copy it.
Legality note: some ornamental fish, snails and plants are restricted in parts of Australia, and native fish rules differ by state. The rules change over time, so check your state Fisheries or Biosecurity department before buying anything named here.
Starting from nothing? Read how to set up a fish tank first, then browse the Tank Ideas hub.
Planted Jungle: Fish Tank Ideas for a Lush Look
Dense plants on the back and sides, floating plants on top, a clear swimming lane in the middle. RSPCA Australia recommends about 50 per cent of a tank as plant or decor cover for tropical fish, so this look is also the welfare-friendly one. Start with tough plants from our beginner plants list.
Driftwood and Rock Riverbed
One big piece of wood, a few rocks and a sand or fine gravel floor, laid out like a creek bed. It’s simple and inexpensive, but some rock changes water chemistry. Check every rock and ornament before it goes in. The decoration ideas guide covers what’s safe.
Small Fish Tank Ideas: The Betta Nano
A single betta with floating plants, a leafy corner and a hide. RSPCA Australia gives 20 litres or more as its ideal size for one betta, with 10 litres the absolute minimum, so a bowl or vase kit doesn’t qualify. You still need a heater and a gentle filter. See what size tank a betta needs.
The Open-Layout Goldfish Tank
Goldfish want floor space and a strong filter more than a busy scene. Choose smooth decor, a sand or rounded gravel floor and tough or artificial plants. The goldfish tank guide has the sizes.
Australian Native Biotope
Sand, leaf litter, a wood branch and a shoal of rainbowfish or blue-eyes. It looks like a creek, and it suits our water. Native fish rules depend on the state, and some species are threatened, so read the native fish guide and check with your state department first.
Peaceful Community Tropical Tank
The classic mix: a school, some bottom dwellers and one centrepiece. RSPCA Australia lists corydoras and a shoal of five or more neon tetras as tank mates for a betta in 40 litres or more. It’s a good template, but only after the tank has cycled.
Where to Put It
Pick a level, sturdy stand away from windows and heaters. RSPCA NSW advises keeping tanks out of direct sunlight, which also cuts algae. Water weighs 1 kg per litre, so a 100 litre tank puts about 100 kg on the stand, before the glass and decor.
| Tank size | What works |
|---|---|
| Under 20 litres | Below the RSPCA betta ideal. Go bigger before you add fish. |
| 20 to 40 litres | A single betta, or small plant-focused layouts. |
| 40 to 100 litres | A betta with tank mates, a small community, or a native biotope. |
| 100 litres or more | A goldfish pair or a mixed community with a proper school. |
Check Before You Copy a Setup
- Species and size: does every fish fit the tank at adult size, not shop size?
- Compatibility: will the fish share water peacefully? A photo doesn’t show nipping.
- Materials: rocks, wood and ornaments should be aquarium-safe and rinsed in plain water.
- Cycling: the tank still needs 4 to 6 weeks of cycling before fish, whatever the layout.
- Heat: an Australian summer can push a small tank up fast, so keep it out of the sun.
Related Guides
Keep reading on the same topic:
Frequently Asked Questions
What are simple fish tank ideas for beginners?
A planted community tank or a betta nano. Both are forgiving, and both lean on plants for looks and cover.
What are good small fish tank ideas?
A single betta with plants in 20 litres or more. Anything smaller doesn’t meet RSPCA Australia’s ideal, so a tank under 10 litres isn’t a good idea.
Can I copy a fish tank idea I saw online?
Yes, once you’ve checked the fish, litres and materials. A photo shows a look, not stocking, and it can hide undersized tanks.
