Guide
Great setups for a 30 gallon community tank
More room for bigger schools, a centrepiece, and bottom dwellers. Example combinations.
- 30 gallons gives you real flexibility: you can run two proper schools (8+ fish each), a centrepiece species, and a bottom crew without crowding anyone out.
- Match water parameters first, temperament second: a beautiful stocking list falls apart if half your fish want soft acidic water and the other half need hard alkaline conditions.
- Cycle the tank completely before adding fish - a 30 gallon isn't forgiving of an uncycled spike with a full community load. Budget 4-6 weeks.
- Stock in stages: add one group at a time, wait two weeks, test ammonia and nitrite before adding the next group.
- Filtration should turn the tank volume over at least 6-8× per hour - a 200 lph filter is underpowered for a stocked 30 gallon community.
- Avoid fin nippers with long-finned fish: tiger barbs, serpae tetras, and some danios will shred the fins of angelfish, bettas, or fancy guppies.
Why 30 gallons is a genuinely good size
A lot of beginner guides treat 30 gallons as just a slightly bigger 10 gallon. It isn't. The extra volume changes what's actually possible. Water parameters stay stable longer between water changes, temperature swings are smaller, and most importantly you have enough horizontal swimming space to keep schooling fish in numbers that actually look good. Eight neon tetras in a 10 gallon looks cramped. Eight neon tetras in a 30 gallon, alongside another school and some corydoras, looks like a proper aquarium.
Standard 30 gallon tanks run around 91 cm × 30 cm (36" × 12") footprint. That's enough for most small-to-medium community species to behave naturally. It's not enough for large cichlids, goldfish, or anything that needs territory measured in feet - but for peaceful tropical community fish, it's a solid platform.
The "one inch of fish per gallon" rule gets repeated endlessly and it's genuinely useless. A single 8-inch bichir has different waste output, oxygen demands, and territorial needs than eight 1-inch tetras. Use a proper stocking calculator and think about bioload, swimming zones, and compatibility - not inches.
Setup 1: Two schools and corydoras
This is the most balanced, forgiving layout for a 30 gallon community and the one most experienced fishkeepers default to. Pick two mid-water schooling species that share compatible water parameters, add a group of corydoras to work the substrate, and optionally a single centrepiece fish.
Stocking list
- 8-10 Paracheirodon axelrodi (cardinal tetras) or Paracheirodon innesi (neon tetras)
- 8-10 Trigonostigma heteromorpha (harlequin rasboras)
- 6-8 Corydoras paleatus or Corydoras sterbai
- 1 Trichogaster lalius (dwarf gourami) or a pair of Trichogaster chuna (honey gouramis)
Cardinals, harlequins, and dwarf gouramis all do well at 24-27°C (75-81°F), pH 6.5-7.5, and moderately soft to neutral water. Corydoras sterbai is the better choice if you're running the higher end of that temperature range - they tolerate warmth better than most corys.
The honey gourami is worth considering over the dwarf gourami if you want a hardier fish. Dwarf gouramis have significant disease susceptibility issues - iridovirus (Dwarf Gourami Disease) is widespread in the trade and there's no treatment. Fish from reputable breeders fare better, but it's a real risk with fish sourced from large wholesalers.
Keeping corydoras in groups of two or three because "a few is enough." Corydoras are genuinely social and show much more natural behaviour - foraging together, resting in a pile, active swimming - in groups of six or more. Three corys in a corner looking stressed is a common sight in otherwise well-kept tanks.
Setup 2: Tetra and livebearer mix
Livebearers like platies and mollies are easy to keep, colourful, and active. Paired with a school of tetras and some bottom dwellers, they make a lively, low-maintenance community. One thing to plan for upfront: livebearers breed readily, and in a community tank some fry will survive in plants or hiding spots. If you don't want to deal with offspring, stick to a single sex - all males is usually easier since females can give birth to stored sperm for months after being separated from males.
Stocking list
- 8-10 Hyphessobrycon herbertaxelrodi (black neon tetras) or Hemigrammus bleheri (rummynose tetras)
- 6 Xiphophorus maculatus (platies) - all male, or planned for fry management
- 6-8 Corydoras aeneus (bronze corydoras)
Avoid mixing mollies with soft-water tetras if your tap water is soft and acidic - mollies genuinely do better in hard, slightly alkaline water (pH 7.5-8.2), while rummynose tetras prefer softer, more acidic conditions. Platies are more flexible and handle a broader pH range (7.0-8.0), making them the better livebearer choice for mixed setups.
Rummynose tetras are one of the best "indicator" fish you can keep. Their distinctive red nose fades noticeably when water quality drops - elevated nitrates, temperature stress, or pH swings. They're essentially a living water quality gauge.
Setup 3: Peaceful centrepiece focus
An angelfish as the centrepiece of a 30 gallon is achievable, but it's the setup with the most caveats. Angels grow to around 15 cm (6") body length and are naturally predatory - anything small enough to fit in their mouth will eventually disappear.
Stocking list
- 1 Pterophyllum scalare (angelfish), or a confirmed bonded pair in a tall 30 gallon
- 8-10 Hemigrammus bleheri (rummynose tetras) or Paracheirodon axelrodi (cardinal tetras)
- 6 Corydoras sterbai
Cardinals and rummynose tetras work here specifically because they're fast-moving and large enough as adults (4-5 cm) to avoid being eaten. Don't use neon tetras - adult angels will eat them, and neons are small enough to be an easy target. Keeping the tetra school large (10+) also reduces the risk; an angel is less likely to single out individuals in a tight, fast-moving school.
A pair of angels in a 30 gallon is workable only in a taller tank (45 cm / 18" minimum height) and only if the pair is genuinely bonded. Two unpaired angels in 30 gallons will fight, especially at spawning time. If you want angels, one is usually the safer choice.
Angelfish and dwarf gouramis in the same tank is a combination that often ends badly. Gouramis occupy the same mid-to-upper water column as angels, and angels can become aggressive towards similarly-shaped fish, especially in smaller volumes. It looks good on paper and tends to cause problems in practice.
Setup 4: Hardy and easy - great for beginners
If you're new to the hobby or setting up your first 30 gallon, this setup is deliberately forgiving. The species here tolerate a wider range of water conditions, handle minor parameter fluctuations better, and are generally available as captive-bred stock rather than wild-caught fish.
Stocking list
- 10 Danio rerio (zebra danios)
- 8-10 Tanichthys albonubes (white cloud mountain minnows)
- 6 Corydoras paleatus (peppered corydoras)
- 1 Ancistrus sp. (bristlenose pleco) or 4-6 nerite snails for algae control
The catch with this setup is temperature. Zebra danios thrive at 18-24°C (64-75°F) and white clouds prefer a similar cool range. That's actually an advantage if you're keeping the tank unheated in a temperate climate, but it means this setup doesn't suit a tropical-temperature tank running at 26-28°C. Pick one or the other if your heater is set higher - or embrace the cool-water setup fully and skip the heater.
Bristlenose plecos are excellent algae grazers and stay small (12-15 cm / 5-6"), unlike common plecos which reach 45 cm (18") and are completely unsuitable for a 30 gallon. If your tank is heavily planted and algae isn't an issue, nerite snails do a clean job without any waste contribution from a larger fish. See our best fish for beginners guide for more options that work well in setups like this.
Your filter should process the tank's full volume at least 6 times per hour - for a 30 gallon (114 litres), that means a filter rated at 680+ lph under load.
What most guides miss: the parameter compatibility problem
Most 30 gallon stocking guides list fish that look good together and stop there. What they skip is checking whether those fish actually want the same water. This is the most common reason an otherwise well-planned community starts showing stress, disease, and unexplained deaths six months in.
Before you finalise any stocking list, check the preferred pH and hardness range for every species. If you're keeping cardinal tetras (soft, acidic - pH 5.5-7.0, very soft water) alongside fish that prefer hard, alkaline conditions, one group will be living outside its preferred range permanently. Fish can survive outside their ideal parameters for a long time - but they'll show it eventually through faded colour, suppressed immune function, and shorter lifespans.
Know your tap water before you buy fish. A simple liquid test kit gives you your pH and hardness baseline. Then choose fish that match your tap water rather than trying to heavily modify water chemistry for every water change. Chasing unstable chemistry is harder than just working with what comes out of your tap. Full detail on what to measure and why is in our aquarium water parameters guide.
Cycling and stocking gradually
A fully stocked 30 gallon community produces a significant ammonia load. Adding all your fish at once into an uncycled or partially cycled tank is one of the most reliable ways to kill them. The nitrogen cycle needs to establish beneficial bacteria colonies sized to handle your bioload - and that takes time. A fish-in cycle is possible, but it means testing daily, doing emergency water changes, and watching fish suffer through ammonia and nitrite spikes. A fishless cycle done properly before any fish go in is easier on everyone.
Once the tank is cycled, stock in stages. Add one group, wait two weeks, test ammonia and nitrite, confirm they're reading zero, then add the next group. This gives your filter bacteria time to adjust to each increase in bioload. Read the full process in our guides on how to cycle a fish tank and the nitrogen cycle explained.
App-aquatic lets you log water test results over time so you can see exactly when ammonia and nitrite drop to zero during your cycle - and spot any spikes after adding new fish. It's a cleaner record than a notebook and easier to share with a fish store if you need advice.
Ongoing maintenance
A 30 gallon community tank needs a weekly water change of 25-30%. Some fishkeepers push to every two weeks, and in a lightly stocked, well-planted tank that can work - but a fully stocked community will accumulate nitrates quickly. The only way to know your specific tank's rhythm is to test. If nitrates are climbing above 20-25 ppm between changes, you're either changing too infrequently or carrying too many fish. Our guide on how often to do water changes covers this properly.
Filter maintenance often gets neglected. Rinse filter media in old tank water (never tap water - chlorine kills your beneficial bacteria) every 4-6 weeks, or when you notice flow dropping. Don't replace all media at once - stagger it so you're not wiping out your biological filtration in a single session.
Track your parameters and get care reminders with App-aquatic.
Get the free appCan I keep a betta in a 30 gallon community tank?
Sometimes, but it depends on the individual fish and the tankmates. Bettas vary hugely in temperament - some are fine in a peaceful community, others will attack anything with flowing fins or bright colour. If you try it, avoid fin-nipping species entirely, don't add other gouramis or labyrinth fish, and have a backup plan (a separate tank) if the betta becomes aggressive. Peaceful, fast-moving tetras like rummynose or black neons are lower risk than slow-moving or fancy-finned fish.
How many fish can I actually keep in a 30 gallon?
It depends on the species, your filtration, and how well you maintain the tank. The stocking lists in this guide are sensible baselines - around 25-30 small community fish plus corydoras is realistic with good filtration and regular water changes. Use a stocking calculator that accounts for bioload, not just fish count, and test your water regularly rather than assuming you're fine.