Best Fish for Small Aquariums

Small aquariums are perfect for beginners, apartment dwellers, or anyone who wants a beautiful fish tank without taking up too much space. However, choosing the right fish is essential. Not all fish are suitable for small tanks, and the wrong choice can lead to stress, poor water quality, or even fish loss.

In this guide, we’ll explore the best fish for small aquariums, along with care tips, tank size recommendations, and common mistakes to avoid.

🐠 What Is Considered a Small Aquarium?

A small aquarium typically ranges from:

• 5 gallons – nano tank
• 10 gallons – ideal beginner size
• 15–20 gallons – small but more stable

Smaller tanks require more careful maintenance because water conditions can change quickly.

🐟 Best Fish for Small Aquariums

1. Betta Fish

Tank Size: 5–10 gallons
Temperament: Semi-aggressive
Care Level: Easy

Betta fish are one of the most popular choices for small aquariums. They are colorful, active, and can live comfortably alone.

✔ Thrive in small tanks
✔ Don’t need tank mates
✔ Beautiful fins and colors

⚠️ Avoid keeping two male bettas together.

2. Guppies

Tank Size: 5–10 gallons
Temperament: Peaceful
Care Level: Easy

Guppies are lively, colorful, and beginner-friendly.

✔ Very hardy
✔ Easy to feed
✔ Fun to watch

Keep only a few in small tanks, as they reproduce quickly.

3. Neon Tetras

Tank Size: 10 gallons
Temperament: Peaceful schooling fish
Care Level: Moderate

Neon tetras are small, colorful, and active. They do best in groups of 6 or more.

✔ Bright blue and red colors
✔ Peaceful community fish
✔ Great for planted tanks

4. Endler’s Livebearers

Tank Size: 5–10 gallons
Temperament: Peaceful
Care Level: Easy

Endlers are similar to guppies but smaller and more active.

✔ Hardy and beginner-friendly
✔ Bright colors
✔ Low maintenance

5. Celestial Pearl Danios (Galaxy Rasboras)

Tank Size: 10 gallons
Temperament: Peaceful
Care Level: Moderate

These tiny fish have stunning spotted patterns and do well in planted tanks.

✔ Unique appearance
✔ Peaceful behavior
✔ Great for nano aquariums

6. Pygmy Corydoras

Tank Size: 10 gallons
Temperament: Very peaceful
Care Level: Easy

Unlike regular corydoras, pygmy corys stay very small and are perfect for nano tanks.

✔ Great bottom cleaners
✔ Social fish
✔ Fun to watch

7. Chili Rasboras

Tank Size: 5–10 gallons
Temperament: Peaceful
Care Level: Moderate

These tiny red fish are ideal for planted nano tanks.

✔ Extremely small
✔ Bright red coloration
✔ Peaceful schooling fish

8. Dwarf Gourami

Tank Size: 10 gallons
Temperament: Semi-peaceful
Care Level: Moderate

Dwarf gouramis are colorful and interactive.

✔ Eye-catching colors
✔ Good centerpiece fish
✔ Calm behavior

Avoid overcrowding to prevent stress.

🚫 Fish to Avoid in Small Aquariums

Some fish grow too large or need more space:

❌ Goldfish
❌ Angelfish
❌ Cichlids
❌ Plecos (common types)
❌ Oscars

These fish require large tanks and strong filtration.

🧼 Tips for Keeping Fish in Small Aquariums

✔ Choose the Right Filter

A gentle but efficient filter is essential to keep water clean.

✔ Avoid Overcrowding

Less fish = healthier tank.

✔ Perform Weekly Water Changes

Change 20–30% of the water every week.

✔ Don’t Overfeed

Feed small amounts once or twice daily.

✔ Add Live Plants

They help maintain water quality and reduce stress.

🧪 Best Tank Size for Beginners

Tank Size	Difficulty	Recommended
5 Gallons	Medium	⚠️ Limited
10 Gallons	Easy	✅ Best Choice
20 Gallons	Very Easy	⭐ Ideal

A 10-gallon tank is the perfect balance for beginners.

✅ Final Thoughts

Small aquariums can be just as beautiful and enjoyable as large ones—if stocked correctly. Choosing the right fish, maintaining water quality, and avoiding overcrowding are the keys to success.

Remember:

✔ Choose small, peaceful fish
✔ Don’t overstock
✔ Maintain clean water
✔ Be patient

With the right care, your small aquarium can thrive and become a stunning centerpiece in your home.