Should parameter targets be preset or user-defined?

Both, in that order. Ship sensible defaults per tank type so a new user is not typing twelve ranges before their first test, and make every one editable, because experienced keepers run deliberately different targets and an app that argues with them gets deleted. Store the targets per tank rather than globally.

Do I need test-strip photo scanning?

Not in version one, and possibly not ever. Colour-matching a strip from a photo is unreliable under real bathroom lighting and produces confidently wrong numbers, which is worse than no feature at all in an app whose entire purpose is trustworthy data. Fast manual entry with the last value prefilled is a better use of the same effort.

How to Build an Aquarium Care App with AI (2026)

What a aquarium care app needs

Log water parameters per tank with trend charts
Safe-range alerts when a value drifts
Recurring maintenance schedule with reminders
Livestock and plant records with added dates
Dosing and feeding log

The screens

Screen	What it does
Tanks	Each tank with last test date and any parameter out of range
Log Test	Enter the parameters you actually test, not all twelve
Trends	Charts per parameter with the safe band shaded
Maintenance	Water changes, filter media, and overdue tasks
Livestock	Fish, corals, and plants with dates added and losses

The data model

Tank: name, volumeLitres, type (freshwater | planted | reef), startedAt
Reading: tankId, parameter, value, unit, measuredAt
ParameterTarget: tankId, parameter, safeMin, safeMax
Task: tankId, title, cadenceDays, lastDoneAt, nextDueAt
Livestock: tankId, commonName, scientificName, quantity, addedAt, removedAt, notes
DoseEntry: tankId, product, amountMl, dosedAt

The build prompt (copy this)

Paste this into ShipNative and it becomes a working React Native app with these screens, navigable in a live preview, in about two minutes:

“An aquarium care app for hobbyists with one to four tanks. Each tank has its own set of tracked parameters and its own safe ranges, because a reef tank and a planted freshwater tank care about completely different numbers — let the user choose which parameters appear on the log form so entry stays fast. Logging a test writes a timestamped reading per parameter, and the trends screen charts each parameter over time with the safe band shaded behind the line, so drift is visible before it is a problem. When a reading falls outside the safe range, surface it on the tank card rather than firing an alarming push notification. Maintenance tasks recur on a cadence in days — water change every 7, filter media every 30 — and show as overdue on the home screen with a one-tap complete that reschedules the next due date. Livestock records track what was added and when, including losses, because a death two weeks after an addition is the pattern people need to see. Screens: Tanks, Log Test, Trends, Maintenance, Livestock. Works offline.”

Then iterate with small, screen-specific prompts (“make the primary button bigger”, “add an empty state”), preview on your own phone, and export the full Expo project whenever you want. The full method: how to build an app with AI.

How it makes money

Subscription is a hard sell here and worth being honest about: the audience is small, technical, and well served by spreadsheets. A one-time purchase ($8-15) for multi-tank support and chart history is the realistic model, and the strongest version of this app is niched down hard — reef-only, with the parameters and target ranges preloaded — rather than trying to serve every kind of tank.

Implementation and the revenue math for every model: how to make money from an app. When you’re ready to ship: App Store and Google Play publishing guides.

Build it now

The prompt above is free to run at shipnative.dev — working aquarium care app on your phone today, full code export, no credit card.

How to Build an Aquarium Care App with AI