Danio

Track your aquarium's water, feedings, and maintenance — nothing else.

Everything you enter stays on your device. No account, no server.

Danio logs what a freshwater tank actually needs day to day

Water parameters
pH, ammonia, nitrite, nitrate, temperature, GH, KH, TDS, plus one custom parameter.
- pH
- Ammonia
- Nitrite
- Nitrate
- Temperature
- GH
- KH
- TDS
- Custom
Livestock

Species typed in by hand, no closed database to hit a wall on.
Maintenance and reminders

Water changes and feedings. Maintenance tasks repeat on the schedule you set, with reminders when something's due.

Free

One tank, unlimited entries, import and export.

Paid

Unlimited tanks and the full parameter charts: unlocked with a monthly, yearly, or one-time purchase — family sharing included on all three.

Restore a purchase (new phone, reinstalled the app)

Settings → Restore Purchases. Works for lifetime and subscriptions.

Cancel a subscription

Subscriptions are managed by Apple, not by Danio. iPhone Settings → [your name] → Subscriptions → Danio → Cancel.

Refunds

Handled by Apple, not by Danio. Request one at reportaproblem.apple.com.

Move to a new device

Your data restores automatically with your iCloud backup, or use Export/Import inside the app.

What's free vs. paid

One tank with unlimited entries and import/export — free. Unlimited tanks and the full parameter charts — unlocked with any plan.

Deleting the app

Deletes its data. There's no account to close, because there's no account.

Freshwater aquarium tracker