Tank Answers
211 straight answers with the real computed numbers, one per question and tank size. What heater, what filter, how many fish, how much substrate, how big a water change, and the minimum tank size for popular species.
📋 Size Guides
One-page stocking and equipment plans for every standard tank size.
🌡️ Heater Size
The exact heater wattage each tank size needs, with one-heater or two guidance.
🌀 Filter Size
Target GPH turnover and the rated filter to actually buy for each tank size.
🐟 Stocking
How many fish each tank size really holds, with worked species examples.
🪨 Substrate
How many pounds of gravel or sand each tank size needs for a 1 to 2 inch bed.
🚰 Water Changes
Weekly water change volumes and dechlorinator doses for each tank size.
📏 Species Minimums
The minimum tank size for popular freshwater species, with tankmates.
Want to run your own numbers?
Every answer here comes from our free calculators. Plug in your exact tank and conditions for a custom result.
Open the Calculators