A 30 gallon tank is where things start to feel spacious. You’re no longer squeezing fish into tight limits. You can build real schools, keep more expressive species, and design a layout that looks intentional instead of crowded.
If you’ve already explored smaller setups like our fish for a 20 gallon aquarium guide, you’ll notice that 30 gallons gives you more room for behavior, territory, and stronger filtration options. And if you’re comparing all sizes, it helps to review the full Aquarium Fish by Tank Size guide to see how each upgrade level changes your options.
Why a 30 Gallon Tank Changes Your Options
At 30 gallons, several important things improve:
- Waste is diluted more effectively
- Larger schools become realistic
- Semi-active and mildly territorial species fit better
- Aquascaping flexibility increases
- Compatibility problems decrease (when stocked correctly)
This size is still manageable for beginners but offers enough volume for intermediate hobbyists to experiment with more interesting fish combinations.
In my opinion, 30 gallons is the first tank size where you can create a visually impressive community without constantly worrying about overstocking.
30 Gallon Standard vs 30 Gallon Long
Tank shape matters again here.
30 Gallon Standard
- Taller tank
- Good for fish that use vertical space
- Works well with angelfish (single or pair with caution)
30 Gallon Long
- More horizontal swim room
- Better for large schooling fish
- Ideal for active species like danios or larger tetra groups
If your goal is a community with strong schooling behavior, I recommend a 30 gallon long whenever possible.
How Many Fish Can You Keep in a 30 Gallon Tank?
Forget strict “inch per gallon” rules.
Instead, think in structure:
- 1–2 centerpiece fish (depending on species)
- 12–15 small schooling fish
- 6–8 bottom dwellers
- Optional algae grazer (if bioload allows)
A balanced 30 gallon tank should feel active but not frantic. If fish constantly bump into each other, you’ve pushed it too far.
Quick Planning Table
| Category | Suggested Count | Notes |
| Centerpiece fish | 1–2 | Depends on temperament |
| Small schooling fish | 12–15 | Bigger groups look better |
| Corydoras/loaches | 6–8 | Keep same species |
| Pleco/algae grazer | 0–1 | Choose small species only |
Best Centerpiece Fish for a 30 Gallon Tank
This is where you can finally explore slightly larger or more expressive fish.
Angelfish
Unlike smaller tanks, a single angelfish can work in a 30 gallon, especially a tall version. A breeding pair may need more space long term, so monitor aggression carefully.
Pearl Gourami
Peaceful, elegant, and ideal for planted tanks. One male or a calm pair can work well.
Bolivian Ram
Great for a calm, warm community tank. A pair can work if territory is respected.
Apistogramma
Dwarf cichlids become more stable in 30 gallons because they have room to establish territory.
Best Schooling Fish for a 30 Gallon Aquarium
This is where larger schools really shine.
Cardinal Tetra
A school of 15 in a planted 30 gallon tank looks impressive and natural.
Rummy Nose Tetra
They reward stable water and look stunning in coordinated groups.
Harlequin Rasbora
Hardy and easy to manage. A larger group reduces stress.
Congo Tetra
One of the few larger tetras that fit in 30 gallons, but keep group sizes moderate and tank long.
Bottom Dwellers for a 30 Gallon Tank
With extra space, you can keep more comfortable group sizes.
Corydoras
Full-sized cory species thrive in 30 gallons. Aim for 6–8 of the same species.
Kuhli Loach
Better in this size than in smaller tanks because hiding spaces don’t overcrowd the tank.
Bristlenose Pleco
A single bristlenose can work comfortably in a 30 gallon, provided filtration is strong.
Semi-Aggressive Fish That Can Work in 30 Gallons
30 gallons gives enough room for slightly stronger personalities.
Kribensis
A pair can establish territory without dominating the entire tank.
Rainbow Shark
Only consider one, and avoid mixing with similar bottom-dwelling territorial fish.
Tiger Barb
Works best in a species-focused tank with a proper group size (10+).
Careful planning prevents aggression problems.
Fish to Avoid in a 30 Gallon Tank
Even at this size, some fish still outgrow the tank.
- Common goldfish
- Oscar and other large cichlids
- Silver dollar fish
- Large plecos (non-bristlenose types)
- Arowana species
If a fish grows past 8–10 inches or needs large territories, 30 gallons is not enough long term.
Sample 30 Gallon Stocking Plans
Balanced Planted Community
1 Pearl Gourami 15 Cardinal Tetras 8 Corydoras
Why it works: peaceful zones and strong schooling.
Angelfish Community (Tall Tank Recommended)
1 Angelfish 12 Rummy Nose Tetras 6 Corydoras
Why it works: angelfish has vertical space; schooling fish stay mid-water.
Semi-Aggressive Setup
1 Pair Kribensis 12 Harlequin Rasboras 1 Bristlenose Pleco
Why it works: defined territories with open swim space.
Active School Tank (30 Long Recommended)
15 Zebra Danios 8 Corydoras 1 Bristlenose Pleco
Why it works: energy is balanced by space.
Planted 30 Gallon Tank Layout Ideas
A 30 gallon allows:
- Larger driftwood centerpieces
- Rock structures with caves
- Carpet plants (if lighting supports it)
- Natural territory divisions
The more sight breaks you add, the fewer aggression issues you’ll see.
Filtration and Equipment for a 30 Gallon Tank
- Strong hang-on-back or canister filter recommended
- Heater sized appropriately for tropical fish
- Lid for jumpers
- Moderate to strong lighting for planted setups
Don’t under-filter. A 30 gallon tank benefits from good water turnover.
Maintenance Routine for Stability
- 25–35% weekly water change
- Gravel vacuum in open areas
- Monitor feeding
- Check water parameters monthly
Consistency keeps even larger communities stable.
Frequently Asked Questions
Is 30 gallons enough for angelfish?
Yes for a single adult. A pair may need more room depending on aggression.
Can I keep two gouramis in 30 gallons?
Sometimes, but watch behavior. One male is usually safest.
How many tetras can I keep in 30 gallons?
12–15 small tetras is a comfortable range depending on tank mates.
Is 30 gallons beginner friendly?
Yes. It’s more stable than smaller tanks and easier to manage than very large aquariums.
What’s better — 20 gallon or 30 gallon?
If you have space and budget, 30 gallons gives noticeably more flexibility and reduces stocking limitations.
Final Thoughts
A 30 gallon tank gives you room to build a real community without stepping into large, high-maintenance territory. It supports larger schools, more expressive centerpiece fish, and stronger biological stability.
If you’re building out your OceanBitez tank-size cluster, this page should sit naturally between your 20 gallon aquarium guide and future larger tank articles like 40 gallon setups.
