KoiLog replaces the soggy notebook by the skimmer: water tests with koi-safe range charts, a temperature-driven feeding guide, growth tracking for every fish — all stored privately on your iPhone.
No account. No cloud. Yours forever.
Everything a koi keeper logs
Log a full water test in seconds with wet hands. KoiLog remembers which parameters you test and charts every reading against koi-safe ranges.
Temperature, pH, ammonia, nitrite, nitrate, KH, GH, dissolved oxygen, TDS and salt — with green/amber/red range dots and trend charts with safe-range bands.
A profile for every fish: 20+ varieties, photos, source, value and status. Length and weight charts show your tosai becoming jumbo.
Reads your latest water temperature and tells you exactly how to feed — including when not to feed at all.
Recurring tasks with local reminders: water changes, filter cleans, UV bulbs, net checks. Complete a task and it reschedules itself.
Koi are freshwater fish — but when treatment calls for salt, KoiLog doses it exactly for your volume, split into safe stages. Free forever.
Medication history with an active-treatment day counter, plus a photo journal of everything that happens at the pond.
Cold water is normal water
Koi are cold-water fish. KoiLog covers the whole year — from summer growth feeding to full winter dormancy — driven by your own temperature readings.
Private by design
Your pond is your business. KoiLog has no sign-up, no server, no analytics and no tracking — every reading, photo and note lives on your device, and CSV export means your data is never locked in.
accounts required. Open the app and start logging.
bytes of your data sent anywhere. There is no backend at all.
tap to export everything you've ever logged as CSV.
Simple, honest pricing
No subscription required — the lifetime purchase is the whole point.