How Many Betta Fish in an 89 Gallon Tank?

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An 89-gallon aquarium is a large tank that provides plenty of flexibility for keeping bettas.

With this much water volume, you can create a thriving betta sorority, use dividers for males, or design a stunning community tank.

However, understanding betta behavior is essential before deciding how many can live in this setup.

Understanding Betta Fish Behavior

  • Male bettas are territorial and cannot live together in the same open space. They must be housed alone or separated with dividers.

  • Female bettas can live together in groups (sororities) if the tank is well-planted and has plenty of hiding spots.

  • Bettas enjoy calm water, stable temperatures, and plenty of enrichment.

How Many Betta Fish in an 89-Gallon Tank?

  • Male Betta Fish: Keep 1 male betta if the tank is open. With dividers, you can house 8–12 males, giving each around 7–10 gallons of space.

  • Female Betta Fish: A tank this size is perfect for a sorority of 14–16 females, provided the tank is heavily decorated to reduce aggression.

Why This Stocking Works

  • Bettas need their own territories.

  • Female sororities spread out aggression in larger groups.

  • The large water volume provides stability and swimming space.

Tank Setup Tips for an 89-Gallon Betta Aquarium

Filtration & Water Quality

  • Use a filter that supports large tanks with a gentle flow.

  • Perform 20–30% weekly water changes.

  • Regularly test ammonia, nitrites, and nitrates.

Heating & Temperature

  • Maintain water at 76–82°F.

  • Use a heater sized for large tanks or dual heaters for even coverage.

Aquascaping & Hiding Spots

  • Add live plants, driftwood, caves, and rocks.

  • Create natural territories with decorations.

  • Floating plants help reduce stress.

Tankmates for Bettas in an 89-Gallon Tank

Good Tankmates:

  • Corydoras catfish

  • Neon or ember tetras

  • Kuhli loaches

  • Mystery snails

Avoid:

  • Fin-nipping fish

  • Aggressive species

  • Multiple males without dividers

Pros of an 89-Gallon Betta Tank

  • Room for a large sorority or multiple divided males

  • Stable water quality due to higher volume

  • Plenty of aquascaping opportunities

Cons of an 89-Gallon Betta Tank

  • More costly and time-consuming to maintain

  • Sorority aggression requires monitoring

  • Large size needs more equipment

Conclusion

In an 89-gallon tank, you can safely keep 1 male betta, several males with dividers, or a female sorority of 14–16 bettas.

With thoughtful aquascaping, proper tankmates, and regular care, this tank size creates an excellent home for bettas while offering room for creativity.

FAQs

1. Can I keep multiple males in an 89-gallon tank?
Only with dividers—otherwise, they will fight.

2. How many female bettas in an 89-gallon tank?
Around 14–16 in a sorority setup.

3. Can a single betta live happily in 89 gallons?
Yes, but enrich the space with plants and tankmates.

4. Do I need multiple heaters for an 89-gallon tank?
Yes, two heaters are recommended for even temperature control.

5. Is an 89-gallon tank good for beginners?
It’s stable but may be costly and harder to manage than smaller tanks.

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