Wild conditions and aquarium recommendations
This is the distinction that most often turns a good source into bad advice. A database records that a species occurs between 22 °C and 28 °C; a care sheet reproduces that as a recommended range; a keeper holds a fish at the top of it for five years and cannot understand why it did not live as long as the books said.
Short answer
A measurement of the water a species was found in and a recommendation for the water it should be kept in are different claims. They look identical once written down as a pair of numbers, and AquariumHQ stores them separately for that reason.
The two claims, and how to tell them apart
An environmental measurement answers: where has this animal been found. It is a fact about a river, recorded by somebody who was measuring the river. It includes conditions the species tolerates, conditions it merely passes through, and conditions at the edge of its range where the population is marginal.
A husbandry recommendation answers: what should this animal be kept in. It is a judgement about a captive environment held constant for years, and it is usually narrower than the measured range — sometimes much narrower, and occasionally centred somewhere else entirely.
| Environmental measurement | Husbandry recommendation | |
|---|---|---|
| Answers | Where has it been found | What should it be kept in |
| Held constant? | No — it varies daily and seasonally | Yes, for years |
| Includes extremes? | Yes, including marginal populations | No |
| Who states it | A survey, a checklist, a database | AquariumHQ, as an editorial position |
| What it is evidence of | The species' tolerance | Nothing, on its own |
Why a wide band is not automatically a generous one
Several records in this catalogue publish temperature bands spanning twenty-five degrees or more — koi, the fathead minnow, the desert goby, the roundtail paradisefish. Those are not statements that any temperature in the range is fine. They describe a seasonal cycle: a temperate fish that overwinters near freezing and feeds in summer warmth is not being offered a choice, it is being described across a year.
Holding such a species at the top of its range permanently removes the winter it is built around. For the roundtail paradisefish that means it will not spawn; for koi it means feeding a fish whose digestion has effectively stopped. Neither shows up as an obvious symptom, which is why the band needs reading as a cycle rather than as a tolerance.
What AquariumHQ does with each
- Source values from environmental databases are recorded as tolerated-range or wild-observed, and an audit fails the build if one is ever reclassified as a recommendation.
- The band published on a species page is AquariumHQ's own editorial position, labelled as one, and where the record can say why it carries a written rationale rather than a bare number.
- Where a published band sits outside everything recorded for a species, that gap is detected, reported and has to be argued in prose. A recommendation sharing no overlap at all with the measurements is treated as a claim that the measurements are wrong.
- Where no defensible figure exists, the parameter is published as unknown with a stated reason. That is a legitimate answer and is preferred to a plausible invention.
What to do with a range you have found elsewhere
- Ask what kind of number it is before using it. A survey figure and a care-sheet figure are not interchangeable even when they agree.
- Check whether the source publishes at species level. Several trade bodies publish care sheets by group, so a figure attributed to one species may be a figure for a family.
- Treat a value repeated identically across many unrelated species as a default rather than a measurement. AquariumHQ screens its own evidence for exactly this and reports the results.
- Prefer stability to precision. Almost every species in this catalogue tolerates a wider range than it tolerates being moved around inside.