FishBaseHQ
Simple aquarium setup suitable as a quarantine or hospital tank

Health · 10 min read

Quarantine tank

A sponge filter and two weeks. Cheaper than ich in the display.

How to set up a simple freshwater quarantine tank, how long to hold new fish, and what to watch for before they touch the display.

Photo: Unsplash

Most display disasters start with “I only added three tetras.” Quarantine is a spare box of water so ich, velvet, and flukes blow up somewhere that is not your scaped tank.

Bare setup

You do not need a second aquascape.

  • 10–20 gallons for community fish. Bigger for big fish.
  • Sponge filter and air pump. Easy to medicate around. Cheap.
  • Heater and a thermometer.
  • PVC elbow or a cave. Nothing you cannot bleach.
  • Nets and a siphon that never touch the display.

Cycle it, or keep media seeded from the main filter in a bag of tank water. A dry sponge is not a filter.

How long

2–4 weeks. Watch for spots, flashing, clamped fins, rapid breathing, and whether they eat. Two days of “they look fine” is how ich finishes its life cycle in the display instead.

Some people prophylactically treat for ich in QT when the source is a rack tank. Know the meds and whether you have scaleless fish or shrimp in there. Do not copy a forum stack.

Workflow

  1. Acclimate into QT, not the display.
  2. Observe daily. Feed lightly.
  3. If symptoms show, treat in QT. Finish the course.
  4. Then move to the display. Do not move the QT water.

“I do not have space”

A plastic tote with a sponge filter is better than nothing for hardy fish for a couple of weeks. If QT is truly impossible, buy less often, from a source you trust, and watch the display like you mean it for two weeks. Accept the risk instead of pretending it is zero.

After disease in the display

The QT becomes a hospital. Move fish when you can. Keep the sponge running. Bleach décor and nets before they go back. Shared gear is how you reseed the pretty tank.

Related