Fish-Only Saltwater vs Full Reef Tank

A fish-only with live rock (FOWLR) tank focuses on marine fish without corals. Lighting can be simple; alkalinity and calcium matter less unless you keep coralline algae. A full reef adds coral-specific lighting, stable major elements, and more frequent testing.

Many keepers start FOWLR and add corals later — but retrofitting lighting and flow costs money. Planning reef from the start avoids buying two sets of gear.

ReefDiary supports both tank types; set tank mode so parameter targets and reminders match what you actually keep.