Hillstream river tank

Save the Little Fish demo · Medium, 30–40 gal · strong current, like a river or rapids · running 741 days · shared October 2026

A cool, fast stream: smooth stones, strong flow, lots of oxygen. Too cold for most tropical fish.

Looks good

The fish

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Loaches · Sewellia

Sewellia lineolata

Fast mountain streams of central Vietnam · rapids

Photo: 5snake5, CC0

× 4

They graze the stones all day.

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Rasboras & danios · DanioStaple

Danio rerio

Streams and paddies of India and Bangladesh · stream

Photo: Roundish, CC0

× 8

Love playing in the current.

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Rasboras & danios · TanichthysStaple

Tanichthys albonubes

Mountain streams near Guangzhou, China · stream

Photo: Ethmostigmus, CC BY-SA 4.0

× 8

Shared range 20–22°C
Every species is comfortable in this range.
No hybrid risk
No two species here can cross, so any fry that turn up are pure.
Stocking 57% of capacity
A rough estimate based on adult body size and tank volume.
Fish at every level
Something at the top, in mid-water and on the bottom, so the whole tank looks alive.
Add strong flow
Some of these fish come from fast rivers. Run a powerhead along the bottom for flow and oxygen.
Tank size is a guess
Size and stocking checks use a typical tank of the size you picked. Add the real length and volume for a sharper answer.
Some values are estimates
Care data for Hillstream loach, White cloud mountain minnow, Zebra danio is estimated or taken from the genus, not yet checked against a source.