Distribution
2,900 checklist statements across 306 aquarium species — what a named source actually said about where each animal occurs, and whether it got there on its own.
Occurrence is not origin
A record that a species is present somewhere says nothing about how it got there. Reading a cloud of sighting records as a native range is how an aquarium escapee becomes a range extension in somebody’s dataset. Every statement here comes from a checklist that either coded the establishment means or did not, and where it did not, AquariumHQ leaves it uncoded rather than filling it in.
Three questions the data answers
- IntroducedA checklist states the species arrived here with human help. That is not a statement that it is established, harmful or illegal.155 species
- NativeA checklist states the species occurs here naturally.83 species
- Recorded as invasiveA checklist states the species is invasive here. AquariumHQ reproduces that assessment; it does not make one.5 species
Why native range is the harder half
The catalogue holds far more statements about where these animals have been taken than about where they are from. That is a property of the literature, not of the animals or of the source.
A national checklist exists to record what is present in a country. “Introduced” gets coded because it is the exceptional, policy-relevant case that funds the work; “native” is the unmarked default and usually goes unstated. There are global programmes dedicated to tracking introductions. There is no equivalent global programme dedicated to asserting nativeness — so across this entire catalogue, only five datasets assert it at all.
| Dataset asserting native status | Statements |
|---|---|
| Catálogo Taxonômico da Fauna do Brasil | 176 |
| Lista Roja de la Fauna Venezolana 2015 | 28 |
| World Register of Marine Species | 21 |
| South African National Species Checklist | 6 |
| Listado taxonómico de peces y lampreas con distribución en México | 8 |
Eighty-four per cent of the confirmed native statements in this catalogue come from one national catalogue, which is also why the confirmed native ranges skew heavily South American. Where no checklist confirms a native range, the organism page says so and presents its range as AquariumHQ’s own reading rather than a citation.
The species that has travelled furthest
Ranked by the number of countries in which a checklist records the species as introduced.
Guppy is recorded as introduced in 94 countries — and is called native by no checklist AquariumHQ holds. That combination is common in this data and is the clearest illustration of the asymmetry above.
Where aquarium species have ended up
Countries with the most catalogue species recorded as introduced. This measures recording effort as much as ecology — a country that surveys its fresh water thoroughly appears higher.
| Country | Catalogue species recorded as introduced |
|---|---|
| MX | 77 |
| US | 65 |
| PH | 51 |
| CO | 46 |
| NO | 42 |
| BR | 41 |
| CA | 35 |
| ID | 25 |
| AU | 22 |
| FR | 22 |
| JP | 22 |
| IN | 21 |
What this data cannot tell you
- Introduced is not invasive. One is a statement about how an animal arrived; the other is a claim about harm. 5 species in this catalogue carries a source-stated invasive record.
- Neither is a legal status. Legality lives in named instruments on the organism pages, and a species being established somewhere says nothing about whether keeping it is permitted there.
- Absence is not evidence. 105 species have distribution records where no source coded the establishment means, and 12 have no checklist record held at all.