Compatibility

Compatibility is not a yes or no. AquariumHQ derives an assessment from stored traits — temperature, pH and hardness overlap, predation in both directions, fin-nipping, territory, zone competition, flow and substrate — and shows the reasoning alongside the verdict.

How to use this

2139 pairings have their own page, chosen by the opportunity engine from the organisms most widely kept. Start from a species below to see everything assessed for it, or assess any pair in the catalogue on demand with the compatibility checker.

Start with one animal

Each species page lists every pairing assessed for it, grouped by verdict, with the dimensions that decide its pairings counted across all of them.

Shrimp (3)

Fish (59)

Snail (3)

Crayfish (1)

Red swamp crayfish65

Pairings to avoid

Combinations the engine assesses as a poor match or worse, most-contested first. These are the ones most worth knowing before a purchase.

Verdict distribution

Across every pairing with a published page. A catalogue where almost everything came out compatible would be evidence of a broken engine rather than a peaceful hobby.

Verdict	Pairings	What it means
Poor match	536	Workable only in unusual circumstances.
Incompatible	517	Should not be attempted.
Conditional	455	Workable if the stated conditions are met.
Generally compatible	442	Requirements align with little or nothing to qualify.
Compatible	189	Requirements align with little or nothing to qualify.