Best Fish for a 30 Litre Tank UK
Quick answer
A 30 litre (≈ 8 US gallon) tank suits nano species under 4 cm in small groups. Top choices:
- Single male betta + 5–10 amano shrimp/snails
- 6–8 chili rasboras (Boraras brigittae)
- 6 ember tetras (Hyphessobrycon amandae)
- 6–8 endler's livebearers (males only, to avoid breeding chaos)
- 6 sparkling gouramis (Trichopsis pumila)
- 10–15 cherry shrimp + 2–3 nerite snails
- 6 scarlet badis (Dario dario)
- 10–15 dwarf shrimp of any Neocaridina colour
A 30 L tank is small. Don't try to put a community of 15 different species into it. Pick one centrepiece + maybe a clean-up crew, and stop.
Why size matters more than people think
A 30 L tank holds about 6 buckets of water. That's enough for nano fish that evolved in puddles, leaf litter, and slow tributaries — but completely unsuitable for fish that evolved in rivers and lakes.
Common fish that shouldn't live in a 30 L:
- Neon tetras — need 60 L for a proper shoal of 8+
- Guppies — too prolific; tank fills with fry in 3 months
- Mollies — get to 8-10 cm, need 80 L+
- Angelfish — adult body size 15 cm, needs 200 L+
- Goldfish — not tropical, plus needs 100 L+ for one fish
- Plecos — common pleco grows to 30 cm
- Discus, large cichlids, anything "interesting" — too big
A 30 L is a nano specialist tank, not a beginner's "any fish will do" tank.
Buying 5 different species at the local pet shop because "they all look small." Three months later they're either dead, fighting, or breeding uncontrollably. Pick ONE feature species, then maybe a clean-up crew. That's it.
Top 8 fish for a 30 litre tropical tank (detailed)
1. Single male betta + clean-up crew (BEGINNER FRIENDLY)
A betta in a 30 L tank is palace living for them. Heavy planting, gentle flow, 25-27 °C, plus 5-10 amano shrimp and 2 nerite snails as inverts. Bettas tolerate shrimp/snails better than other fish.
Browse our betta range — many strains available.
2. Chili rasboras (Boraras brigittae) — 6-8 fish
Tiny (1.5 cm), bright red, peaceful schoolers. Soft acidic water (pH 6.0-7.0), 24-27 °C. Need a planted tank with floating plants — they won't shoal in a bare tank.
3. Ember tetras (Hyphessobrycon amandae) — 6 fish
Glowing orange, 2 cm adult size, very peaceful. Easier than chili rasboras (more tolerant of harder UK water). Group of 6-8 looks stunning in a planted tank.
4. Endler's livebearers — 6 males
Smaller cousin of the guppy. Bright, peaceful, easier than guppies because you can buy males-only and avoid breeding. 2-3 cm adult, very hardy, tolerate UK tap water without adjustment.
5. Sparkling gourami (Trichopsis pumila) — 6 fish
Iridescent dwarf gouramis, 4 cm adult. Make tiny "croaking" sounds when displaying. Need a quiet tank with floating plants. Very peaceful.
6. Cherry shrimp colony — 10-15 + snails
A pure shrimp tank in 30 L is one of the easiest, most rewarding setups. 10 starting cherry shrimp will multiply to 30-50 within months. Add 2-3 nerite snails for algae control.
7. Scarlet badis (Dario dario) — 6 fish
Tiny (2 cm) micro-predator from India. Stunning red-and-black males. Need live food (frozen bloodworm, daphnia) — they often refuse pellets. Specialist but rewarding.
8. Nano shrimp species mix
Cherry + crystal red + Amano in different small groups — a "shrimp aquarium" is the safest, most colourful 30 L option for absolute beginners.
What about cool species you can't keep at 30L?
| Species | Why not | Tank size needed |
|---|---|---|
| Neon tetras | Need 60 L for proper shoal | 60 L+ |
| Guppies | Breed prolifically — overcrowded fast | 60 L+ for males-and-females |
| Bristlenose pleco | Grows to 12 cm; high bioload | 80 L+ |
| Corydoras | Need a sandy bottom area + group of 6 | 60 L+ |
| Dwarf gourami | Adult 8 cm; territorial | 60 L+ |
| Angelfish | Adult 15 cm body, taller fins | 200 L+ |
| Discus | Adult 20 cm; needs warmer water + group | 250 L+ |
| Any cichlid | Most reach 10 cm+ adult | 80 L+ |
If you really want neon tetras, corydoras, or a community — upgrade to a 60 L tank before you start. It's £20 extra and saves months of frustration.
Equipment you need for a 30L tropical tank
| Item | Spec | Approx cost |
|---|---|---|
| Tank (30 L glass) | 36 cm x 22 cm x 26 cm typical | £25-50 |
| Internal filter | Rated for 50 L (oversized) | £15-20 |
| Heater | 50 W with thermostat | £12-15 |
| Thermometer | Stick-on LCD or digital | £3-8 |
| Substrate | 2-3 cm of inert sand or fine gravel | £10 |
| Plants | Anubias, Java fern, mosses | £15-25 |
| Lighting | LED, 6500 K, ~6-8 W | £25-40 |
| Test kit | API liquid master | £25 |
| Dechlorinator | Seachem Prime or similar | £10 |
| Total kit | £140-200 |
Plus £20-50 for fish/shrimp.
Common 30 L mistakes
Mistake: "It's small, so I don't need a heater"
Why it fails: UK rooms swing 4-6 °C between day and night. Tropical fish need 24-26 °C steady. No heater = cold-stressed fish within weeks.
Fix: Buy a 50 W heater. £12-15.
Mistake: "I'll add fish gradually — start with 8 today, more next week"
Why it fails: Tank isn't cycled. First batch dies from ammonia. Second batch dies the same way.
Fix: Cycle the tank fully (4-6 weeks fishless cycle) before adding ANY fish. See our cycling guide.
Mistake: "The pet shop said this fish stays small"
Why it fails: Pet shop staff sometimes sell fish without knowing the species' adult size. Common pleco grows to 30 cm. Goldfish to 25 cm. "Tinfoil barb" to 35 cm. None of these belong in 30 L.
Fix: Look up adult size on FishBase before buying. Or ask us — every product page on this site lists adult size.
Mistake: "I'll get one of every colour"
Why it fails: 30 L can't sustain 5+ different species. Bioload too high, fights, stress.
Fix: Pick ONE feature species (or one colony of shrimp). Stop.
Summary
A 30 L tank is genuinely useful — for the right species. Stick to nano fish under 4 cm, pick ONE main species, plant heavily, heat properly, and the tank will thrive for years.
If you want a community of 5+ different species, upgrade to 60 L or 100 L — see our 60 L guide and 100 L guide.
Related guides
Frequently asked questions
Browse our UK live-fish range
From this article straight into the catalogue.
Beginner Fish
The best tropical fish for beginners UK — hand-picked easy-care species that thrive with minimal fuss. Perfect starter community tank candidates.
Community Tank Fish
Peaceful tetras, rasboras, corydoras, platies and gouramis chosen to live together — temperament, adult size and water range per listing so the mix works.
Tetras
Premium Tetras for sale UK — Cardinal, Ember, Black Neon, Rummy Nose, Serpae, Diamond, Glowlight and more. Peaceful community schoolers.
Betta Fish
Halfmoon, plakat, koi, giant and wild-type Betta splendens, males and females, tail type and size stated per listing. Bagged singly, live arrival covered.
Guppy
Fancy guppies bred for colour — Moscow, Cobra, Dumbo ear and Endler lines as males, females or pairs. Hardy in UK tap water; arrive alive or replaced.
Cherry Shrimp
Red, blue, yellow, black and Rili cherry shrimp (Neocaridina) graded per listing, with mature-tank and water guidance so a new colony settles and breeds.
Corydoras
Shop current Corydoras catfish listings in the UK. Compare scientific identity, size and sale unit, with price and availability shown per product.
Freshwater Snails
Shop freshwater aquarium snails in the UK. Compare current species, adult size, water needs, diet, breeding risk, compatibility, prices and availability.
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