Aquarium
Quarantine tank
The single most effective disease-prevention measure available, and the one most often skipped. It needs no substrate, no plants and no decoration beyond a few hiding places — which also makes it easy to observe and easy to disinfect.
Short answer
A simple bare tank with a sponge filter and heater, used to hold new arrivals for observation and to treat sick fish away from the display tank.
What it does
- Isolates new arrivals for observation
- Allows treatment without medicating the display tank
- Holds fish during a display tank emergency
Strengths and where it fits
Strengths
- Prevents introduced disease reaching an established tank
- Treatment doses are cheaper and more accurate in a small bare tank
- Avoids exposing the display tank's biological filter and invertebrates to medication
Good fit for
- Every new fish
- Any sick fish that can be moved
- Any tank where invertebrates rule out medication
Limitations and where it is the wrong choice
Limitations
- Needs its own cycled filter — keep a spare sponge running in the display tank
- Additional cost and space
- Bare tanks stress some species; provide pipes or pots for cover
Poor fit for
- Whole-tank parasite treatments where the parasite is already in the display tank
Sizing
- Two to four weeks of observation is the usual recommendation for new arrivals.
- Keep a spare sponge filter running in the display tank so a cycled filter is always available at short notice.