A 50 gallon aquarium is where your fishkeeping options start to feel wide open. You’re no longer working within tight limits like a 20 or even a 30 gallon tank. Instead, you can build larger schools, keep stronger centerpiece fish, and design aquascapes that look balanced instead of crowded.
If you’ve been comparing mid-size tanks like 30 vs 40 gallons, stepping up to 50 gallons gives you even more flexibility — especially for medium-sized fish and semi-aggressive species. This guide will walk you through what actually works in a 50 gallon tank, realistic stocking limits, and combinations that stay stable long term.
Quick Answer: What Can You Keep in a 50 Gallon Tank?
A 50 gallon aquarium comfortably supports:
- 20–25 small schooling fish
- 1–3 medium centerpiece fish
- 8–12 bottom dwellers
- Controlled semi-aggressive setups
It is large enough for medium cichlids, rainbowfish groups, and larger schooling displays — but still not large enough for giant species like Oscars or common plecos long term.
Now let’s go deeper.
Why a 50 Gallon Tank Is a Major Step Up
The jump from 40 to 50 gallons may not sound dramatic, but it increases:
- Biological filtration capacity
- Territory spacing
- Schooling scale
- Equipment flexibility
- Aquascaping depth
More water volume means more stability. Minor feeding mistakes or temporary parameter changes are less likely to cause sudden problems.
In my opinion, 50 gallons is where fishkeeping becomes far less restrictive and much more creative.
Tank Shape: Standard 50 vs 50 Gallon Breeder
Dimensions matter more than the number on the box.
Standard 50 Gallon
- Often taller
- Good for vertical swimmers
- Works for angelfish and taller aquascapes
50 Gallon (Long or Wide Footprint)
- Better horizontal swim space
- Ideal for rainbowfish, danios, and larger schools
- Easier to divide territories
If you plan to keep active fish or cichlids, prioritize horizontal swimming space.
How Many Fish Can You Keep in a 50 Gallon Tank?
There’s no single number, but structure matters.
A balanced 50 gallon setup often looks like:
- 1–2 medium centerpiece fish
- 18–25 small schooling fish
- 8–10 bottom dwellers
- 1 algae grazer
Avoid mixing too many dominant fish. Even 50 gallons has limits.
Planning Table
| Category | Suggested Range | Notes |
| Medium centerpiece fish | 1–2 | Choose compatible species |
| Small schooling fish | 18–25 | Bigger groups look natural |
| Bottom dwellers | 8–12 | Keep same species |
| Pleco | 0–1 | Select small species only |
Best Centerpiece Fish for a 50 Gallon Tank
This size supports medium fish comfortably.
Angelfish
A group of 4–6 juveniles can grow together in a 50 gallon tank. Monitor aggression as they mature.
Electric Blue Acara
A pair can work very well here. They add color and personality without overwhelming the tank.
Severum
A single severum can thrive in a 50 gallon for a good period, though very large adults may eventually prefer more space.
Pearl Gourami
A small group or pair can look stunning in a planted 50 gallon.
Best Schooling Fish for a 50 Gallon Aquarium
Now you can create impressive group displays.
Boesemani Rainbowfish
Active and colorful. Keep groups with more females than males to reduce chasing.
Congo Tetra
Larger than typical tetras and well suited for 50 gallons.
Rummy Nose Tetra
A large, synchronized school looks dramatic in this size tank.
Silver Dollar
Possible in a 50 gallon when young, but long term they often require larger tanks and group space.
If you want small fish read this Schooling Fish
Bottom Dwellers for a 50 Gallon Tank
With more floor area, bottom fish feel more comfortable.
Corydoras
Larger species can be kept in healthy groups of 8–10.
Kuhli Loach
A larger group works well in planted tanks.
Bristlenose Pleco
One bristlenose is usually ideal. Avoid large common plecos.
Semi-Aggressive Fish That Work in 50 Gallons
A 50 gallon tank gives moderate flexibility for stronger personalities.
Firemouth Cichlid
A pair can work if territory is defined.
Convict Cichlid
Best kept carefully. They breed easily and can dominate smaller tanks.
Kribensis
More stable here than in smaller tanks.
Aggressive setups still require careful planning and hiding spaces.
Fish to Avoid in a 50 Gallon Tank
Even 50 gallons has limits.
- Oscar cichlids
- Arowana species
- Large common plecos
- Fully grown silver dollars (in large groups)
- Giant gourami
If a fish exceeds 10–12 inches and requires large territory, consider 75 gallons or more.
Sample 50 Gallon Stocking Ideas
Large Peaceful Community
20 Rummy Nose Tetras 10 Corydoras 1 Electric Blue Acara
Balanced, active, stable.
Angelfish Display Tank
5 Angelfish (grown together) 15 Cardinal Tetras 8 Corydoras
Monitor adult aggression carefully.
Rainbowfish Community
8 Boesemani Rainbowfish 15 Harlequin Rasboras 1 Bristlenose Pleco
Colorful and energetic.
Semi-Aggressive Setup
Pair of Firemouth Cichlids 12 Congo Tetras 1 Bristlenose Pleco
Requires strong filtration.
Aquascaping a 50 Gallon Tank
This size supports:
- Large driftwood structures
- Rock caves for territories
- Open swim lanes
- Heavy planted backgrounds
Breaking sight lines reduces aggression and improves fish comfort.
Filtration and Equipment
A 50 gallon tank benefits from:
- Strong hang-on-back or canister filter
- Heater rated appropriately
- Secure lid for jumpers
- Lighting suited to plant needs
Under-filtering is a common mistake at this size.
Maintenance Routine
- 30–40% weekly water change
- Gravel vacuum open areas
- Rinse filter media gently
- Monitor fish behavior
Even large tanks require consistency.
Frequently Asked Questions
Is 50 gallons good for angelfish?
Yes. It supports small groups more comfortably than 30 gallons.
Can I keep two electric blue acaras?
Yes, especially if they form a pair.
How many rainbowfish can I keep?
6–8 medium rainbowfish with additional schooling fish is common.
Is 50 gallons beginner friendly?
Yes, if space and budget allow. Larger tanks are generally more stable.
Is 50 gallons enough for Oscars?
No. Oscars require much larger tanks long term.
Final Thoughts
A 50 gallon aquarium gives you room to build a serious community tank without stepping into very large, high-maintenance territory. It supports medium fish, larger schooling groups, and controlled semi-aggressive setups.
If you’re building out your tank-size cluster on OceanBitez, this article fits naturally after your 40 gallon guide and before larger sizes like 55 or 75 gallons.
