Editorial policy and sourcing
How we choose sources, check numbers and correct mistakes.
What we publish
Reference numbers for standard aquariums, calculators built on stated formulas, and guides on choosing, setting up and keeping a freshwater tank. We do not publish product reviews based on products we have not handled, and we do not accept payment to feature a product or brand.
Sources we use
- Fish data. Adult size, minimum footprint, temperature, pH and behavior come from Seriously Fish species profiles. Where Seriously Fish has no profile or treats a species as a pond fish, we use FishBase, Aquarium Co-Op or Ornamental Fish International and name the source on the page.
- Tank dimensions. Published outside dimensions from tank makers and retailers. When brands disagree by more than about half an inch, the tank page carries a note.
- Physical constants and safety. Government and standards sources: the U.S. Geological Survey for the weight of water, NIST for unit definitions, the International Code Council for floor design loads, and the U.S. Environmental Protection Agency for chlorine and chloramine in tap water.
- Fishkeeping practice. University extension publications (especially the University of Florida IFAS program, which works with the ornamental fish industry), manufacturer instructions, and established hobby references.
Every guide lists its sources at the end, and each factual claim links to the source it came from. When reputable sources disagree, we show both and say which we plan around and why.
Our own estimates
Some numbers are ours: tank weights, the water a tank really holds after gravel, and the stocking percentage. These are marked as estimates, and the method behind each is written out on the relevant calculator page so you can check the arithmetic.
How pages are checked
Numbers on tank and fish pages are generated from a single data file, so a correction fixes every page that uses it. Guides are checked against their sources before publication and again when a source changes. Each guide shows the date it was last reviewed.
Advertising and affiliate links
Ads and affiliate links never decide what we recommend. Gear suggestions follow from the tank’s measurements, such as heater wattage and stand size, and link to an Amazon search rather than a single product so you can compare. See the affiliate disclosure.
Corrections
Send corrections to [email protected]. If we were wrong we fix the page and, for a guide, note the change at the bottom.
Last updated October 19, 2026.