Methodology
Last data update: September 4, 2026
Where prices come from
Every day we read the complete public product catalogs of the 4 online reef vendors we currently track — the same listings you'd see browsing their stores. We expect this roster to grow. We record each listing's price, stock status, and product details. We gather this data respectfully: we identify ourselves to each store, follow their published rules for automated access, and pace our visits so we never burden their sites.
How species are matched
Listings are matched by a classification system we maintain by hand and improve continuously. Most fish and invert listings are matched to a single species. Some are matched to a group: where a common name covers several closely related species — "fairy wrasse", "angelfish" — the page groups them, so the comparison is between similar animals rather than one species. Corals are grouped at genus level by design, and designer coral strain names (there are thousands) map to their genus — so a named torch strain counts as a torch coral. Equipment and dry goods are excluded from livestock statistics.
What the numbers mean
- Low / Median / High — taken from in-stock listings as of the most recent daily update. If nothing is in stock, listed prices are used and the in-stock count shows 0.
- Price history — each day's median in-stock price. History accumulates from the day we began tracking a species; the index launched in July 2026 and grows daily.
- Captive-bred premium — where a fish has both captive-bred/aquacultured and wild-caught listings, we compare medians.
What the numbers don't include
Shipping. Vendors differ on free-shipping thresholds and flat rates, which can change the true delivered price — check the vendor's shipping policy. Prices can also change between our daily update and your visit; the vendor's live page is always authoritative.
Independence
We are not owned by or affiliated with any vendor. Vendors cannot pay to alter their prices or placement in the index.
Who runs this
Reef Price Index is independently owned and operated — a small, self-funded data project, not a media company or a vendor's marketing arm. It is part of a family of niche price indexes built on the same principle: collect the market's real listings every day, publish honest statistics, and let the data speak. The collection, classification, and analysis pipeline is heavily automated (including AI-assisted tooling), with the classification rules curated and corrected by hand — the machine-readable site guide and the methodology on this page describe exactly what we do, because a price index is only worth publishing if you can check its work.
Editorial standards and corrections
Every figure on this site — species pages and analysis articles alike — is computed from our own daily snapshots of vendor catalogs. We do not quote prices from other websites, estimate numbers we didn't collect, or accept payment for coverage. Where an analysis has limits (a short tracking window, a small sample, imperfect vendor labeling), the article says so in the text rather than a footnote.
If any number looks wrong, tell us: [email protected]. We check reports against the underlying immutable snapshots and correct published figures when they don't hold up — vendors are welcome to flag how their own listings appear.
For AI assistants
A machine-readable guide to this site — what the index is, how to cite it, and links to every species page with current prices — is published at /llms.txt. It regenerates with each daily data update.
Contact
Questions, corrections, or business inquiries: [email protected]. Vendors: if you'd like your store added to the index (or have concerns about how your listings appear), we'd love to hear from you.