How Many Tiger Barbs in a 40 Gallon Tank?
About 6–8 — based on adult size, bioload, and real water volume.
About 6–8 tiger barb
Photo via Wikimedia Commons
In a 40-gallon tank you can comfortably keep about 6–8 tiger barb — enough for a proper school, on their own with good filtration and regular water changes. Add fewer if you're mixing in other species.
How we get that number
An adult tiger barb reaches about 3.0" and has a moderate bioload. Working from real water volume and waste output (not the old one-inch-per-gallon myth), a 40-gallon tank supports roughly 6–8 of them. Because tiger barb are schooling fish, keep them in a group of at least 8 — never just one or two. They need 68–79°F water at pH 6–8.
Build your exact stocking with the calculator → Full tiger barb care guide →
Gear for a 40-gallon tank
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FAQ
How many tiger barb can I keep in a 40 gallon tank?
About 6–8 tiger barb, kept on their own with good filtration. Add fewer when combining with other species — use the stocking calculator to be sure.