AquaAssist is a free aquarium tracker that goes beyond basic logging. It includes a guided nitrogen cycle assistant for new tanks, a species database with compatibility checks before you add new fish or plants, and a CO2 estimator for planted setups. It's a PWA that installs on both Android and iOS and works fully offline once loaded — no app store, no account, no sign-up. The only optional feature, cross-device sync, uses a short code instead of email or login.
