A slender, silvery schooling fish native to Australia. They are pelagic and found in huge numbers in the wild across freshwater rivers, billabongs, and brackish estuaries. Known for their distinct cucumber-like odor when handled. In the aquarium, they are highly sensitive to handling and require mature, stable water with plenty of open swimming space. Best kept in single-species setups or with very peaceful, temperate tank mates.
Australian Smelt At a Glance
Australian Smelt Tank Requirements
Will Australian Smelt fit in your tank?
Care guides tell you what Australian Smelt needs, the next question is whether your tank can safely provide it. Test Australian Smelt against your tank size, maintenance needs, and the fish you already keep before you buy.
Australian Smelt Water Parameters
Australian Smelt Temperament & Compatibility
Australian Smelt Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard
The wild-type and standard form of the Australian Smelt. They must be kept in schools to feel secure and prevent stress. Extremely sensitive to being netted (which can easily dislodge their fragile scales); it is recommended to catch them using solid containers rather than abrasive nets.
Same care requirements as the base species
Also known as: Wild Type
Australian Smelt Care Guide Summary
The Australian Smelt, scientifically known as Retropinna semoni, belongs to the Other family group. Adults reach a maximum size of approximately 7.5 cm and have a fusiform body shape with a fast growth rate. Classified as peaceful, this species primarily occupies the surface and mid-level zones of the aquarium and produces a low level of biological waste.
To thrive, the Australian Smelt requires a brackish tolerant aquarium with a minimum volume of 75 litres and a tank length of at least 60 cm. Water temperature should be maintained between 15°C and 24°C, with a pH range of 6.5–8 and a general hardness of 5–20 dGH. A moderate water flow is preferred.
The Australian Smelt is a rewarding species to keep, provided its core environmental needs are met. The Australian Smelt is typically available in one standard form.
Australian Smelt Habitat Setup
When setting up an aquarium for the Australian Smelt, a moderate water flow best suits their natural preferences. Because this species occupies the surface and mid-level zones, the aquarium layout should prioritise adequate surface area with floating cover to make them feel secure near the waterline and open swimming space in the centre of the tank for free movement. Useful additions include smooth gravel or rounded substrate to protect their sensitive barbels and light plant coverage for partial shade. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Australian Smelt Compatibility Notes
Classified as peaceful, the Australian Smelt is a schooling species that feels most secure in a sizeable group, where natural shoaling behaviour reduces stress and brings out their best colours. Selecting tankmates that favour different water layers from the surface and mid-level zones can help reduce competition and territorial overlap.
Who Australian Smelt Is Actually For
Australian Smelt is best for a fishkeeper who wants a species that can settle into a calmer community setup and can provide a keeper who can commit to a proper group of at least 6. It makes the most sense for a hobbyist who will actually build around its needs, especially plants.
The most common mistake is buying Australian Smelt for looks first and only later discovering how its adult size, behavior, or bioload changes the whole tank plan. Another frequent problem is underestimating its social needs. A token pair or trio often behaves very differently from a real group.
Australian Smelt Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Australian Smelt.
20 Gallon High
20 Gallon Long
29 Gallon Standard
30 Gallon Breeder
36 Gallon Bowfront
40 Gallon Breeder
Show 17 more tank sizes
Frequently Asked Questions About Australian Smelt
How big does Australian Smelt get?
Australian Smelt (Retropinna semoni) typically reaches a maximum adult size of approximately 7.5 cm. They have a fusiform body shape and a fast growth rate.
What tank size does Australian Smelt need?
A minimum aquarium volume of 75 litres and a tank length of at least 60 cm are recommended for Australian Smelt. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Australian Smelt need?
Australian Smelt thrives in brackish tolerant conditions with a temperature range of 15–24°C, a pH between 6.5 and 8, and a general hardness of 5–20 dGH. A moderate water flow is preferred.
Is Australian Smelt peaceful or aggressive?
Australian Smelt is classified as peaceful with an aggression score of 1 out of 10. They are generally well-suited to peaceful community tanks.
How many Australian Smelt should be kept together?
Australian Smelt is a schooling species and should be kept in groups of at least 6. Larger groups help distribute aggression and encourage natural schooling behaviour.
Does Australian Smelt have any special tank requirements?
Yes. Australian Smelt benefits from plants - lighly covered and smooth gravel (sensitive barbels) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Australian Smelt need a lid on the tank?
Yes. Australian Smelt is a known jumper, and a tight-fitting lid or cover is essential to prevent escape. Even a small gap can be enough for a determined fish to leap out.
Useful setup supplies
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Guidarium Editorial Desk
Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.
- Last reviewed
- April 30, 2026
- Last updated
- April 30, 2026
- Issues or corrections?
- Contact the editorial team
Top Tank Mates for Australian Smelt
These fish are strong compatibility matches for Australian Smelt based on water preferences, temperament, adult size, and tank behavior.
Spotted Hillstream Loach
Gastromyzon punctulatus
Ideal Tank MatesTrapdoor Snail
Cipangopaludina chinensis
Ideal Tank MatesGolden Bristlenose Pleco
Ancistrus sp. L144
Ideal Tank MatesAssassin Snail
Anentome helena
Ideal Tank MatesBristlenose Pleco
Ancistrus cf. cirrhosus
Ideal Tank MatesSnowball Shrimp
Neocaridina cf. zhangjiajiensis var. white
Ideal Tank MatesPlants That Suit Australian Smelt
These plants pair well with Australian Smelt based on shared water preferences, layout fit, and how likely they are to hold up in the same aquarium.
African Onion Plant
Crinum calamistratum
Afzel's Anubias
Anubias afzelii
Anacharis
Egeria densa
Ashy Pipewort
Eriocaulon cinereum
Baby Tears
Lindernia rotundifolia
Balansae
Cryptocoryne crispatula
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