Practical guide

Keep a Tropical Fish Breeding Logbook

A breeding log turns each project into evidence. It prevents repeated mistakes and protects the integrity of strains or location-coded fish.

Freshwater focusWelfare-firstUpdated July 2026

Identify the fish

Use a pair or group ID, source, acquisition date, strain, species and known relationship.

Record events

Note conditioning changes, courtship, spawning, birth, hatch, free-swimming date, parental removal and transfers.

Connect water to outcomes

Add temperature, pH, hardness and nitrogen-waste readings around important events.

Track offspring

Record approximate number, first foods, survival, growth, sex separation and destination.

Be honest about uncertainty

Write “unknown” rather than inventing parentage, hatch dates or purity. The browser-based breeding log can export a CSV for your own records.