Great setups for a 40 gallon community tank

Setup 1: Three schools

10–12 neon or cardinal tetras, 10–12 harlequin rasboras, 8–10 corydoras, 1–2 dwarf gouramis or a pair of rams. Strong filtration and weekly water changes.

Setup 2: Angelfish community

2 angelfish, 12–15 rummynose or cardinal tetras (avoid very small nippable species), 8 corydoras. Tall tank preferred for angels. Plenty of plants and vertical space.

Setup 3: Rainbowfish and friends

6–8 rainbowfish (e.g. Boeseman's or dwarf neon), 10–12 tetras or rasboras, 8 corydoras. Rainbows need hard water; match other species to your water parameters.

Setup 4: Mixed peaceful

8 black neon tetras, 8 cherry barbs, 8 platies, 8 corydoras, 1 bristlenose pleco or nerite snails. Lots of colour and activity without aggression.

General tips

40 gallons gives room for larger schools and a more impressive display. Still respect bioload and compatibility. Canister or dual HOB filtration often works well. Cycle thoroughly and add fish in groups. Log water parameters in App-aquatic.

Quick takeaways

• 40 gallons suits multiple schools, centrepiece(s), and a solid cleanup crew.
• Match species to water hardness and temperament; avoid mixing fin nippers with long-finned fish.
• Strong filtration and regular water changes; cycle first and stock gradually.