How we source and write this

Where the data comes from

The structured facts on a species page (adult size, minimum tank size, temperature, pH, hardness, diet, temperament, taxonomy, range) are aggregated from public reference databases:

• GBIF and WoRMS for taxonomy, accepted names, and distribution
• FishBase and SeaLifeBase for size, environment, depth, and biology
• SeriouslyFish, The Aquarium Wiki, and Aqua-Fish.net for hobbyist care data: tank size, water parameters, temperament, behavior
• Tropica for aquatic plants (light, growth rate, CO₂, placement)
• Corals of the World for coral habitat and identification

Photography is handled separately and credited per image. See image credits and licensing.

How disagreements between sources are settled

Sources contradict each other constantly, so the merge is rule-based rather than first-one-wins:

• Numeric ranges (temperature, pH, hardness, adult size) take the widest range across all sources that reported one. A range that is too wide is a smaller problem than one that is confidently too narrow.
• Categorical fields (temperament, diet, care level) follow a fixed source priority, preferring sources that record the field explicitly over ones where it has to be inferred from prose.
• Behavior flags (schooling, nocturnal, territorial, jumper) are set if any source reports them, on the grounds that a warning you did not need beats a warning you never got.
• Units are normalized on ingest, including a check that catches temperatures recorded in Celsius where the field expects Fahrenheit.

Where AI is used

The prose on species pages (the description, care notes, and breeding notes) is drafted by a large language model working from the structured facts above plus the source text collected for that species. This is deliberate. Rewriting thousands of species entries by hand was not realistic for one person, and copying the source text would have been plagiarism.

What that means in practice, stated plainly:

• Drafts are checked against the source text for copied phrasing before they are published, so the wording is ours even where the facts are not.
• The model is given the database facts to write from, so the numbers in the prose should match the numbers in the fact table beside it. If they ever disagree, trust the table and please tell us.
• Every page has been generated and reviewed at the batch level, with spot checks and correction passes across the catalog, but not every one of several thousand pages has been individually read by a human. Errors will exist. That is what the correction process below is for.
• Structured numbers are never invented by the model. They come from the sources listed above, and a field with no source is left blank rather than filled in.

Where AI is not used

• Compatibility checks are ordinary code, not a model guess. They compare water type, temperature and pH overlap, predator-to-prey size ratios, temperament, and reef safety, on top of a set of hand-curated overrides for well-known pairings that the rules get wrong.
• Stocking and bioload math in the builder is a deterministic model. The same tank gives the same answer every time.
• The guides in Learn are written and edited by hand, because that is where judgment matters most and where being subtly wrong does the most damage.
• Photographs are real photographs of real animals. The few AI-generated illustrations on the site are badged as such on the image itself.

Pages we deliberately do not build out

The catalog includes several thousand species, mostly deep-water corals, that are documented in scientific databases but never kept in home aquariums. There is no honest care guide to write for them. Those entries are marked as taxonomic records rather than care pages: they are kept out of the browse listings and search index, they carry no care rating, and they carry no advertising. They stay reachable by direct link because the taxonomy is still worth having.

Corrections

If something here is wrong, tell us and it gets fixed. That includes a wrong parameter range, a misidentified photo, a species listed in the wrong water type, care advice that would hurt an animal, or a description that reads as though it were written about a different fish.

Email [email protected] with the species page and what is wrong. Corrections that affect animal welfare get handled first. If you are a photographer and want a credit changed or an image pulled, that is covered on the credits page and the answer is always yes.