Inch-per-gallon is goldfish-bowl advice. Count waste, not inches.

A 10-inch oscar is not ten neon tetras. Adult size and mess class decide whether the tank stays cycled.

Points: small (≤2") = 1, medium (2–5") = 3, large (5–10") = 8, XL (10"+) = 14. Messy fish (goldfish, common plecos) count one class up. Capacity ≈ gallons in points if filtration and water changes are real.

Use it in 10 minutes. Add the adult sizes you actually want, not the 1-inch juveniles at the store. Stay under the tank's point cap. Heater: roughly 3–5 W/gal for a 10°F rise. Filter: about 5× tank gallons per hour.

Tank recipes

Tank	Capacity (pts)	Heater (78°F from 68°F)	Filter GPH (5×)
10 gal	10	50 W	50–80
20 gal long	20	75–100 W	100–150
29 gal	29	100–150 W	150–200
55 gal	55	200–250 W	275–350
75 gal	75	250–300 W	375–500

Same bioload table as aquarium-stocking.com. Planted tanks buy maybe 10–20% headroom — don't spend it all.

Worked 20-long: 10 ember tetras (10 pts) + 6 cherry shrimp (ignore) + 1 nerite is a community, not a circus. The bala shark that 'only needs a 20' wants 150 gallons as an adult. Don't.

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