What AquariumStocking is for

Free tank recipe card — print it, 10 minutes.

Stocking calculator for freshwater aquarium keepers.

Not reef or saltwater. Inch-per-gallon is goldfish-bowl advice.

This map lists pages that exist. It is not a keyword dump and it does not treat every article as its own niche. The calculator (or the pack) is the hub. Guides sit under one pillar each.

Bioload stocking

Count adult waste, not inches.

• Stocking calculator — Bioload points, heater, filter, water changes.
• Tank recipe card — Printable 10/20/29/55/75 gal recipes.
• How many fish per gallon — Why the inch rule fails.

Worked example

The 20-long everyone actually buys.

• Fish in a 20 gallon — A community, not a circus.

Filtration

Normal level: 5 turnovers an hour, then this calculator's 20% step.

• Filter for a 20 gallon — Turnover that matches the bioload.
• Heater and filter size chart — Maker watts and rated flow, each chart on its own row.

Heat

A 20-gallon tank from 68°F to 78°F is 100 watts on this calculator.

• Heater wattage — ΔT math and two-heater redundancy.
• Heater and filter size chart — Published bands from Aqueon, EHEIM, and Fluval. Accessed October 6, 2026.

How the numbers are made

• Methodology and editorial standards — Formulas already on the calculator, the spec-chart rules, and the affiliate policy.

Embed

• Embed the calculator — Free iframe. Keep the credit link.

Questions

Sourced data

• Freshwater fish size and tank data — Adult size and minimum tank for 16 species with a CSV you can download.
• What size heater for a 20 gallon tank — Choosing between 50 and 100 watt heaters.

One question per page. Species figures are the Seriously Fish profile linked on the line. Heater bands are from Aqueon heater wattage guidelines. Accessed Oct 2, 2026.

• What size tank a betta fish needs — 18 × 12 in base, about 11 US gallons (Seriously Fish).
• What size tank neon tetras need — 24 × 12 in base, about 14 US gallons, group of at least 8-10 (Seriously Fish).
• What size tank an angelfish needs — 39 × 16 × 20 in smallest tank, about 53 US gallons (Seriously Fish).
• What size tank guppies need — 18 × 12 × 12 in, about 11 US gallons (Seriously Fish).
• What size tank an oscar needs — 60 × 24 in base, about 143 US gallons for a single adult (Seriously Fish).
• What size tank zebra danios need — 36 × 12 in base, about 21 US gallons (Seriously Fish).
• What size tank a bronze cory needs — 31 × 12 in base, about 19 US gallons, group of at least 4-6 (Seriously Fish).
• What size tank platies need — 24 × 12 × 12 in, about 14 US gallons (Seriously Fish).
• What size tank mollies need — 36 × 12 × 12 in, about 21 US gallons (Seriously Fish).
• What size tank a bristlenose pleco needs — 31 × 12 in base, about 19 US gallons for a couple (Seriously Fish).
• What size tank a German blue ram needs — 24 × 12 in base, about 14 US gallons for a pair, gentle flow (Seriously Fish).
• What size tank a dwarf gourami needs — 24 × 12 × 12 in, 56 liters, for a pair (Seriously Fish).
• What size tank cherry barbs need — 24 × 12 in base, about 14 US gallons, school of at least 6-10 (Seriously Fish).
• What size tank harlequin rasboras need — 24 × 12 in base, about 14 US gallons, group of at least 8-10 (Seriously Fish).
• What size tank a discus needs — about 48 × 18 × 18 in, 255 liters (Seriously Fish).
• What size heater a 10 gallon tank needs — 50 watts, the 5-20 gallon band (Aqueon).
• What size heater a 29 gallon tank needs — 100 watts, the 15-40 gallon band (Aqueon).
• What size heater a 40 gallon tank needs — 100 watt and 150 watt bands both include 40 gallons (Aqueon).
• What size heater a 55 gallon tank needs — 150 watt and 200 watt bands both include 55 gallons (Aqueon).
• What size heater a 75 gallon tank needs — 200 watt and 300 watt bands both include 75 gallons (Aqueon).
• How many fish in a 75 gallon tank — Which species fit a 48½ × 18½ in. base (Aqueon).
• What size tank for a Jack Dempsey — A 48 × 18 in. base for one adult pair (Seriously Fish).

Care

Water, feeding, and the first fish. Each page runs at least one example through the calculator on the home page. Published October 3, 2026.

• Cloudy water in a new tank — Test before you treat it.
• How to add fish — Quarantine at least 30 days, then a small first group.
• How much to feed tropical fish — 0.5–1% of body weight, one feeding a day for most pets.
• How to treat sick fish — Water test first. No doses.
• How to keep pet fish alive — Cycle, test, then stock a 20-gallon starter.
• Koi in a 500-gallon pond — Aquarium math labeled as aquarium math, plus SRAC water limits.
• Humane euthanasia — AVMA 2020 wording. A veterinarian performs it.
• Fish in a 10, 29, or 55 gallon tank — Each size through the calculator. Published October 6, 2026.
• How often to change aquarium water — The percent comes from the nitrate rise you measure.

Sisters

Adjacent math lives next door, not here. GeneratorSizer · Battery Bank Sizer