The short answer
A 30 litre tank is a nano, so plan for one small shoal plus a cleanup crew rather than a mixed community. A solid setup is 6–8 micro-fish — chili rasboras, ember tetras or a small group of endlers — with dwarf shrimp and maybe a snail. A single betta with shrimp also suits 30 litres nicely. Keep it to one fish species and stock lightly.
Forget inch-per-gallon
That old rule fails because it ignores what actually loads a tank: a fish’s adult size, its bioload, whether it schools, its temperament and your filtration. Thirty litres is more workable than a 10 litre nano, but it is still small enough that water parameters move quickly. Choose species by their real needs and leave headroom.
Sensible 30 litre stocking ideas
- 6–8 chili rasboras + a small cherry shrimp colony
- 6–8 ember tetras with a snail cleanup crew
- A trio of male endlers kept lightly stocked
- 1 betta with shrimp or a nerite snail
Avoid active or larger schoolers (neon tetras want more room, danios need swimming lanes, corydoras prefer a bigger footprint). Nothing that grows past a couple of centimetres really belongs here. Live plants help too: they soak up nitrate between water changes and give shy nano fish the cover they need to feel secure.
Before you add anything
Always cycle the tank before adding livestock, then introduce fish a few at a time. Keep up weekly water changes and read our fuller guide on how many fish you can keep. Ready for a proper community? See how many fish in a 50 litre tank or browse the best nano aquariums.