Tropical Fish Community Tank Guide — Compatible Combinations & Precautions

Keeping multiple tropical fish in one tank—a "community tank"—is one of the greatest joys of the aquarium hobby. However, wrong combinations can lead to bullying or even cannibalism. This article covers basic rules for successful community tanks, plus recommended and prohibited combinations.

Basic Community Tank Rules

1. Match Water Quality Requirements

Fish with significantly different pH and temperature preferences shouldn't be kept together. For example, characins that prefer slightly acidic water and African cichlids that prefer slightly alkaline water mean one group is always stressed.

2. Consider Body Size

Fish that fit in another's mouth will be eaten. Mixing large and small fish is generally a no-go. Always check adult sizes.

3. Factor in Temperament (Aggression)

Territorial or aggressive fish chase and stress others. Even same-species individuals, especially males, often fight.

4. Distribute Swimming Layers

Combining surface swimmers, mid-level swimmers, and bottom dwellers creates a lively tank and reduces territorial disputes.

Recommended Combinations

Classic Community Tank

• Neon Tetra × Corydoras: Mid-level tetras with bottom-dwelling corydoras—the ultimate classic
• Guppy × Platy × Molly: Same livebearer family with similar water preferences—excellent compatibility
• Rasbora × Otocinclus: Mid-level schooling fish with glass-cleaning algae eaters—an ideal pairing

For Planted Tanks

• Cardinal Tetra × Apistogramma (female community): Red and blue characins complement green plants, with small cichlids preferring rock caves at the bottom
• Cherry Shrimp × shrimp-safe small fish: Clown Killifish or Microrasbora—ultra-small fish that don't eat shrimp combined with shrimp

Combinations to Absolutely Avoid

Male Bettas Together

Male Bettas fight viciously when they spot each other. They may battle until one dies. Always keep singly or with visual barriers.

Large Predators × Small Fish

Arowana, Snakehead, Piranha, etc. see small fish as food. Community keeping with mouth-sized fish is impossible.

Territorial Cichlids Together

African Cichlids and Discus have very strong territorial instincts, attacking other fish aggressively especially during spawning. Sufficient space and hiding spots are needed in the same tank.

Angelfish × Small Tetras

Mature Angelfish may eat small fish like Neon Tetras. No problems as juveniles, but issues arise after growth.

Tank Size and Community Keeping

Smaller tanks can't provide enough territory, leading to bullying. General guidelines:

• 30cm tank: Up to 5-8 small fish (3-4cm size)
• 45cm tank: 10-20 small fish, or 1 cichlid pair
• 60cm tank: Diverse community possible. 20-30 fish community tank
• 90cm+: Mid-size fish communities and luxurious planted aquascapes possible

Before starting a community tank, we recommend setting up basic keeping conditions per our Tropical Fish Beginner's Complete Guide. On Bri-Choku, you can purchase healthy breeder-raised guppies, corydoras, and more directly.