12/8/2025
Tank Setup

Quarantine Tank Setup: A Simple System for New Arrivals

Why a bare tank beats a decorated one here

A quarantine tank doesn't need substrate, plants, or decor — in fact, a bare-bottom setup is preferable because it lets you see waste and uneaten food immediately, and makes any medication treatment far easier to dose accurately without decorations absorbing it.

A 10-20 gallon tank with a sponge filter, seeded from an established tank's filter media, a heater, and a simple cover is enough. Running a spare sponge filter continuously in your main tank's sump or filter box, ready to move into a quarantine setup the moment it's needed, means you're never starting quarantine biology from zero during an actual emergency.

The quarantine tank you set up in a panic is never as effective as the one that was already running.

New fish should spend a minimum of two weeks in quarantine, observed daily for signs of ich, fin rot, or unusual behavior, before joining the main display. For fish from sources with a higher disease history, such as wild-caught imports, three to four weeks is a safer window.

What to actually watch for

Daily observation during quarantine should check for clamped fins, white spots, unusual scratching against surfaces (flashing), labored breathing, and appetite. Catching a problem in an isolated 10-gallon tank is dramatically easier and cheaper to treat than catching it after it's spread through a fully stocked display.

  • Quarantine duration: minimum 2 weeks, 3-4 for higher-risk sources
  • Setup: bare bottom, sponge filter, heater, simple cover
  • Keep a spare seeded sponge filter running for instant readiness
  • Daily checks: fins, spots, flashing, breathing, appetite
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