How Many Cherry Barbs in a 40 Gallon Tank?
About 17–21 — based on adult size, bioload, and real water volume.
About 17–21 cherry barb
Photo via Wikimedia Commons
In a 40-gallon tank you can comfortably keep about 17–21 cherry 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 cherry barb reaches about 2.0" and has a low bioload. Working from real water volume and waste output (not the old one-inch-per-gallon myth), a 40-gallon tank supports roughly 17–21 of them. Because cherry barb are schooling fish, keep them in a group of at least 6 — never just one or two. They need 73–81°F water at pH 6–7.5.
Build your exact stocking with the calculator → Full cherry barb care guide →
Gear for a 40-gallon tank
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FAQ
How many cherry barb can I keep in a 40 gallon tank?
About 17–21 cherry barb, kept on their own with good filtration. Add fewer when combining with other species — use the stocking calculator to be sure.